Periodic patterns and electron arrangements

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Notas de aula

Big idea: periodic patterns and electron arrangements

Key concept: Relationships. The proton number identifies the element. Electron arrangements explain periodic patterns; atoms in the same main group have similar outer-shell arrangements.
Related concepts: Models and evidence. Use a scientific explanation to make predictions, then test it against observations.
Global context: Scientific and technical innovation. Predicting chemical properties helps scientists choose materials.

Elements, Compounds & Mixtures

Element: substance made of atoms with the same number of protons; cannot be split chemically.
Compound: pure substance of two or more elements chemically combined; cannot be separated by physical means.
Mixture: combination of substances not chemically combined; separable by physical methods (e.g., filtration).
Examples: element = copper; compound = CO₂; mixture = sand and water.

Particle diagram showing elements, compounds and mixtures

Atomic Structure

Atoms consist of protons, neutrons (in nucleus) and electrons (in shells).
Proton: relative mass 1, charge +1; Neutron: relative mass 1, charge 0; Electron: relative mass 1/1840, charge -1.
Atomic number (Z) = number of protons; determines element and equals electrons in neutral atom.
Mass number (A) = total protons + neutrons; also called nucleon number.
Number of neutrons = mass number – atomic number.

The structure of the carbon atom

Electronic Configuration

Electrons occupy shells (energy levels); first shell holds 2, second 8, third 8 (simplified).
Electronic configuration lists electrons per shell, e.g., carbon = 2,4.
Outermost shell (valence shell) determines chemical properties; full outer shell = stable (noble gas).
Number of occupied shells = Period number; number of outer electrons = Group number (for Groups I–VII).
Ions: e.g., Na⁺ has configuration 2,8 (lost one electron).

Sodium atom: electron configuration 2,8,1

Isotopes

Isotopes: same element, same number of protons, different number of neutrons.
Isotopes have identical chemical properties (same outer electrons) but different physical properties (mass).
Notation: e.g., carbon-14 or ¹⁴C.

Relative Atomic Mass

Relative atomic mass (Aᵣ) = weighted average mass of all isotopes compared to 1/12 mass of carbon-12.
Formula: Aᵣ = (Σ(% abundance × mass)) / 100.
Example: rubidium: (72×85 + 28×87)/100 = 85.6.

Periodic Table & Groups

Elements in same Group have same number of outer electrons and similar chemical properties.
Noble gases (Group 0/VIII) have full outer shells and are unreactive.
Group number for Groups I–VII equals number of outer electrons.
Period number equals number of occupied electron shells.

Think like a scientist

Use a teacher-provided dataset to compare the electron arrangements and properties of elements in a period.
Comparison: the element being compared. Outcome: the electron arrangement and chemical properties.
Control: compare atoms in their neutral state. Explain why this makes the comparison fairer.
Evidence: Use a consistent method, repeated observations where appropriate and a table with labelled quantities and units. Keep unexpected results and investigate their cause.
Safety: Practical activities need teacher supervision and an appropriate risk assessment. Use the provided data or simulation where the investigation specifies it.
Inquiry task: State a testable question, predict the outcome using the science, then explain how your observations would support or challenge the prediction.

Evaluate the science

Predicting chemical properties helps scientists choose materials.
A simple shell model predicts many trends but does not describe the full behaviour of electrons.
Evaluation task: Link your conclusion to evidence, identify a limitation and suggest a specific improvement. Distinguish a measured result from an explanation of its cause.

Slides

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Questões de prática

Prévia grátis — 8 de 45 perguntas. Cadastre-se para ver todas.

1.Which option correctly describes the relative charges and masses of the subatomic particles?
Easy
- AProton +1, neutron 0, electron -1; relative mass of proton 1, neutron 1, electron 0.00054
- BProton +1, neutron 0, electron -1; relative mass of proton 0.00054, neutron 1, electron 0
- CProton 0, neutron +1, electron -1; relative mass of proton 1, neutron 1, electron 0.00054
- DProton +1, neutron 0, electron 0; relative mass of proton 1, neutron 1, electron 0.00054
2.The atomic number of element Q is 9 and its mass number is 19. In which group of the Periodic Table should element Q be placed?
Easy
- AGroup 0
- BGroup I
- CGroup VII
- DGroup II
3.Which two atoms are isotopes?
Easy
- AQ and S
- BQ and T
- CR and T
- DR and S
4.Which of the following statements is correct?
Easy
- AElements contain different atoms
- BCompounds consist of elements that are not chemically combined
- CMixtures consist of elements that are chemically combined
- DA mixture can contain elements and compounds
5.Which statement about carbon is correct?
Medium
- AIt has 4 electron shells.
- BIt has 2 outer shell electrons.
- CIt has 12 nucleons.
- DIt has an electron configuration of 2,8,2.
6.Element X contains 12 of each sub-atomic particle. What is the correct Group number for element X?
Medium
- AGroup 0
- BGroup I
- CGroup VII
- DGroup II
7.The X⁺ ion of element X has 16 electrons and a nucleon number of 37. What is the correct Group number for element X?
Hard
- AVII
- BVIII
- CIII
- DI
8.Which row correctly describes the number of outer shell electrons and properties of isotopes?
Hard
- ANumber of electrons: same; Chemical properties: same
- BNumber of electrons: same; Chemical properties: different
- CNumber of electrons: different; Chemical properties: same
- DNumber of electrons: different; Chemical properties: different

Mais perguntas

9.Iridium has two isotopes, Ir-191 and Ir-193. Calculate the relative atomic mass of iridium using the data: mass number 191 abundance 62.7%, mass number 193 abundance 37.3%.
Hard
- A191.2
- B191.6
- C191.7
- D192.5
10.A selenide ion has the notation ³⁴₇₉Se²⁻. Which row correctly describes the subatomic particles in a selenide ion?
Medium
- AProtons: 79, Neutrons: 34, Electrons: 34
- BProtons: 34, Neutrons: 45, Electrons: 34
- CProtons: 34, Neutrons: 45, Electrons: 36
- DProtons: 45, Neutrons: 34, Electrons: 32
11.A sample of neon consists of three isotopes: Ne-20 (90.9%), Ne-21 (0.3%), and Ne-22 (8.8%). What is the relative atomic mass of neon to one decimal place?
Hard
- A20.2
- B20.0
- C20.9
- D21.0
12.An atom of element X has an electronic configuration of 2,8,6. Which group of the Periodic Table does element X belong to?
Medium
- AGroup VI
- BGroup II
- CGroup VIII
- DGroup VII
13.Copper has two isotopes: Cu-63 and Cu-65. The relative abundance of Cu-63 is 69%. What is the relative atomic mass of copper?
Hard
- A63.6
- B64.0
- C64.4
- D65.0
14.Which statement about isotopes is correct?
Medium
- AIsotopes have the same number of protons but different numbers of neutrons.
- BIsotopes have the same number of neutrons but different numbers of protons.
- CIsotopes have the same number of protons and the same number of neutrons.
- DIsotopes have different numbers of protons and different numbers of neutrons.
15.The relative atomic mass of chlorine is 35.5. Which statement explains this value?
Medium
- AChlorine exists as two isotopes with different masses, and their average is 35.5.
- BChlorine atoms have 35.5 protons and neutrons on average.
- CChlorine has a mass number of 35.5.
- DChlorine-35 and chlorine-37 have equal abundances.
16.A sample of rubidium contains two isotopes: Rb-85 (72%) and Rb-87 (28%). Calculate the relative atomic mass of rubidium to one decimal place.
Hard
- A85.6
- B86.0
- C85.0
- D86.6
17.An atom has the symbol ⁴⁰₁₈Ar. How many neutrons does it have?
Medium
- A22
- B18
- C40
- D58
18.The electronic configuration of a calcium ion (Ca²⁺) is:
Medium
- A2,8,8
- B2,8,8,2
- C2,8,8,1
- D2,8
19.A student measures the mass of a sample of sulfur powder before and after heating it in air. The mass increases. Which statement explains this observation?
Medium
- ASulfur has combined with oxygen from the air to form a compound.
- BSulfur has decomposed into simpler substances.
- CThe heating has caused the sulfur atoms to gain protons.
- DThe sulfur has evaporated and then condensed.
20.A sample of neon is found to contain three isotopes: Ne-20 (90.9%), Ne-21 (0.3%), and Ne-22 (8.8%). What is the relative atomic mass of neon to one decimal place?
Medium
- A20.2
- B20.0
- C21.0
- D20.8
21.Which of the following statements about the relative charge and mass of subatomic particles is correct?
Easy
- AProton: charge +1, relative mass 1; Neutron: charge 0, relative mass 1; Electron: charge -1, relative mass 1/1840
- BProton: charge +1, relative mass 1/1840; Neutron: charge 0, relative mass 1; Electron: charge -1, relative mass 1
- CProton: charge +1, relative mass 1; Neutron: charge +1, relative mass 1; Electron: charge -1, relative mass 1/1840
- DProton: charge 0, relative mass 1; Neutron: charge +1, relative mass 1; Electron: charge -1, relative mass 1/1840
22.In an experiment, a student heats a blue hydrated copper(II) sulfate crystals in a test tube. The crystals turn white and water droplets appear on the cooler parts of the test tube. Which type of change has occurred?
Hard
- AA reversible chemical change
- BAn irreversible chemical change
- CA physical change only
- DA nuclear change
23.Which of the following is the correct definition of an element?
Easy
- AA substance made of atoms that all contain the same number of protons and cannot be split into anything simpler by chemical means.
- BA substance made of two or more different types of atoms chemically combined.
- CA combination of two or more substances that are not chemically combined.
- DA substance that can be separated into simpler substances by physical methods.
24.Which particle has a relative mass of 1 and a charge of 0?
Easy
- AProton
- BNeutron
- CElectron
- DNucleus
25.What is the electronic configuration of a sulfur atom?
Easy
- A2,8,6
- B2,8,8
- C2,6
- D2,8,8,6
26.An atom of element X has 12 protons and 12 neutrons. What is its mass number?
Medium
- A12
- B24
- C36
- D6
27.An atom has the electronic configuration 2,8,7. Which group of the Periodic Table does it belong to?
Medium
- AGroup VII
- BGroup II
- CGroup 0
- DGroup I
28.Which of the following is a mixture?
Medium
- ACarbon dioxide
- BBrass
- CWater
- DSodium chloride
29.A sample of lithium contains two isotopes: Li-6 (7.5%) and Li-7 (92.5%). What is the relative atomic mass of lithium to one decimal place?
Hard
- A6.9
- B6.5
- C7.0
- D6.1
30.Use a teacher-provided dataset to compare the electron arrangements and properties of elements in a period. What is the independent variable?
Easy
- Athe element being compared
- Bthe electron arrangement and chemical properties
- Cthe number of repeated trials
- Dthe scientific explanation written afterwards
31.Use a teacher-provided dataset to compare the electron arrangements and properties of elements in a period. Which observation or quantity is the dependent variable?
Easy
- Athe element being compared
- Bthe electron arrangement and chemical properties
- Cthe title given to the investigation
- Dthe number of references in the report
32.Use a teacher-provided dataset to compare the electron arrangements and properties of elements in a period. Which decision best controls another factor in this comparison?
Medium
- Achange every condition for each trial
- Buse a different measurement method for every result
- Ccompare atoms in their neutral state
- Drecord only results that agree with the prediction
33.Use a teacher-provided dataset to compare the electron arrangements and properties of elements in a period. Why should the class repeat measurements or check multiple comparable observations?
Medium
- ATo guarantee that every systematic error disappears
- BTo make an unsupported prediction become correct
- CTo avoid reporting results that disagree with a model
- DTo assess variation and judge how consistent the evidence is
34.A class is evaluating an application of periodic patterns and electron arrangements. Which statement identifies a relevant limitation?
Hard
- AA simple shell model predicts many trends but does not describe the full behaviour of electrons.
- BAll scientific models reproduce every feature of the real world
- COne favourable result proves that a technology has no disadvantages
- DA conclusion needs no evidence when a scientific term is used
35.Use a teacher-provided dataset to compare the electron arrangements and properties of elements in a period. Which conclusion is most justified by a controlled comparison?
Hard
- AA claim that the result must hold in all possible conditions
- BA conclusion restricted to the tested conditions, with uncertainty and limitations stated
- CA claim that alternative explanations never need testing
- DA claim based only on the most convenient observation
36.Use a teacher-provided dataset to compare the electron arrangements and properties of elements in a period. Select the two practices that strengthen the validity of this comparison.
Medium
- Acompare atoms in their neutral state
- Bchange the measurement method whenever a result is unexpected
- Crecord the electron arrangement and chemical properties using the same agreed procedure
- Dreport only observations that confirm the prediction
37.When evaluating evidence about periodic patterns and electron arrangements, select the two scientifically defensible statements.
Hard
- AOne result proves the explanation in every situation
- BA simple shell model predicts many trends but does not describe the full behaviour of electrons.
- CA conclusion should state the conditions and uncertainty of the evidence
- DModels never need revision when new evidence appears
38.Design a fair investigation for this question: Use a teacher-provided dataset to compare the electron arrangements and properties of elements in a period. Identify what to compare, what to record and one control.
Medium
39.Explain one use of the science in periodic patterns and electron arrangements and evaluate one limitation of the evidence or application.
Hard
40.A neutral atom has electron arrangement 2,8,3. Identify its period and the number of outer electrons.
Hard
- APeriod 2; eight outer electrons
- BPeriod 3; thirteen outer electrons
- CPeriod 3; three outer electrons
- DPeriod 13; three outer electrons
41.An atom has 11 protons and loses one electron. What changes, and what stays the same?
Hard
- AIt becomes a different element with 10 protons
- BIt remains neutral because its nucleus is unchanged
- CIt becomes a -1 ion because an electron left
- DIt becomes a +1 ion but remains sodium
42.Neutral atoms A and B have electron arrangements 2,8,1 and 2,8,8,1. Which comparison is supported?
Hard
- AThey have the same number of outer electrons but occupy different periods
- BThey have equal proton numbers and are the same element
- CThey belong to the same period but different main groups
- DBoth have full outer shells
43.Why are neon and argon relatively unreactive compared with sodium?
Hard
- ATheir atoms contain no electrons
- BTheir outer electron shells are full in the simple shell model
- CThey have no protons and no nucleus
- DAll gases are chemically unreactive
44.Two carbon isotopes have mass numbers 12 and 14. Both have atomic number 6. What differs?
Hard
- AThey have six and eight protons respectively
- BThey are carbon and oxygen because mass determines identity
- CThey have six and eight neutrons respectively
- DThey have different proton numbers but the same neutron number
45.A student assigns a period from the total number of electrons. What correction should be made for a neutral atom with arrangement 2,8,7?
Hard
- AUse seventeen electrons: it is in Period 17
- BUse seven outer electrons: it is in Period 7
- CUse the two first-shell electrons: it is in Period 2
- DUse the three occupied shells: it is in Period 3

Resumos de revisão

## Big idea: periodic patterns and electron arrangements - **Key concept: Relationships.** The proton number identifies the element. Electron arrangements explain periodic patterns; atoms in the same main group have similar outer-shell arrangements. - **Related concepts: Models and evidence.** Use a scientific explanation to make predictions, then test it against observations. - **Global context: Scientific and technical innovation.** Predicting chemical properties helps scientists choose materials. ## Elements, Compounds & Mixtures - **Element**: substance made of atoms with the same number of protons; cannot be split chemically. - **Compound**: pure substance of two or more elements chemically combined; cannot be separated by physical means. - **Mixture**: combination of substances not chemically combined; separable by physical methods (e.g., filtration). - Examples: element = copper; compound = CO₂; mixture = sand and water. ## Atomic Structure - Atoms consist of **protons**, **neutrons** (in nucleus) and **electrons** (in shells). - **Proton**: relative mass 1, charge +1; **Neutron**: relative mass 1, charge 0; **Electron**: relative mass 1/1840, charge -1. - **Atomic number (Z)** = number of protons; determines element and equals electrons in neutral atom. - **Mass number (A)** = total protons + neutrons; also called nucleon number. - Number of neutrons = mass number – atomic number. ## Electronic Configuration - Electrons occupy **shells** (energy levels); first shell holds 2, second 8, third 8 (simplified). - **Electronic configuration** lists electrons per shell, e.g., carbon = 2,4. - **Outermost shell** (valence shell) determines chemical properties; full outer shell = stable (noble gas). - Number of occupied shells = **Period** number; number of outer electrons = **Group** number (for Groups I–VII). - Ions: e.g., Na⁺ has configuration 2,8 (lost one electron). ## Isotopes - **Isotopes**: same element, same number of protons, different number of neutrons. - Isotopes have identical **chemical properties** (same outer electrons) but different **physical properties** (mass). - Notation: e.g., carbon-14 or ¹⁴C. ## Relative Atomic Mass - **Relative atomic mass (Aᵣ)** = weighted average mass of all isotopes compared to 1/12 mass of carbon-12. - Formula: Aᵣ = (Σ(% abundance × mass)) / 100. - Example: rubidium: (72×85 + 28×87)/100 = 85.6. ## Periodic Table & Groups - Elements in same **Group** have same number of outer electrons and similar chemical properties. - **Noble gases** (Group 0/VIII) have full outer shells and are unreactive. - **Group number** for Groups I–VII equals number of outer electrons. - **Period number** equals number of occupied electron shells. ## Think like a scientist - Use a teacher-provided dataset to compare the electron arrangements and properties of elements in a period. - **Comparison:** the element being compared. **Outcome:** the electron arrangement and chemical properties. - **Control:** compare atoms in their neutral state. Explain why this makes the comparison fairer. - **Evidence:** Use a consistent method, repeated observations where appropriate and a table with labelled quantities and units. Keep unexpected results and investigate their cause. - **Safety:** Practical activities need teacher supervision and an appropriate risk assessment. Use the provided data or simulation where the investigation specifies it. - **Inquiry task:** State a testable question, predict the outcome using the science, then explain how your observations would support or challenge the prediction. ## Evaluate the science - Predicting chemical properties helps scientists choose materials. - A simple shell model predicts many trends but does not describe the full behaviour of electrons. - **Evaluation task:** Link your conclusion to evidence, identify a limitation and suggest a specific improvement. Distinguish a measured result from an explanation of its cause.

Relating Electron Config to Periodic Table: Determine the group and period of an element from its electronic configuration.
Calculating Relative Atomic Mass: Calculate the relative atomic mass of an element from the masses and abundances of its isotopes.
Understanding Isotopes: Define isotopes and explain why they have the same chemical properties but different physical properties.
Atomic Structure and Subatomic Particles: Describe the structure of an atom and the properties (relative mass and charge) of protons, neutrons, and electrons.
Writing Electronic Configurations: Write the electronic configuration (electron distribution) for the first 20 elements and their ions.
Calculating Protons, Neutrons, Electrons: Use atomic number and mass number to determine the number of protons, neutrons, and electrons in an atom or ion.
Classifying Substances: Distinguish between elements, compounds, and mixtures based on particle diagrams and definitions.
Designing scientific inquiries: Plan a fair comparison: Use a teacher-provided dataset to compare the electron arrangements and properties of elements in a period.
Evaluating evidence and impacts: Predicting chemical properties helps scientists choose materials. A simple shell model predicts many trends but does not describe the full behaviour of electrons.
Elements, Compounds & Mixtures: **Element**: substance made of atoms with the same number of protons; cannot be split chemically.
Atomic Structure: Atoms consist of **protons**, **neutrons** (in nucleus) and **electrons** (in shells).
Electronic Configuration: Electrons occupy **shells** (energy levels); first shell holds 2, second 8, third 8 (simplified).
Isotopes: **Isotopes**: same element, same number of protons, different number of neutrons.
Relative Atomic Mass: **Relative atomic mass (Aᵣ)** = weighted average mass of all isotopes compared to 1/12 mass of carbon-12.
Periodic Table & Groups: Elements in same **Group** have same number of outer electrons and similar chemical properties.
Element: **Element**: substance made of atoms with the same number of protons; cannot be split chemically.

Flashcards

Which option correctly describes the relative charges and masses of the subatomic particles?

Proton +1, neutron 0, electron -1; relative mass of proton 1, neutron 1, electron 0.00054 Protons have a charge of +1 and relative mass 1, neutrons are neutral with relative mass 1, electrons have charge -1 and relative mass about 1/1840 (0.00054).

The atomic number of element Q is 9 and its mass number is 19. In which group of the Periodic Table should element Q be placed?

Group VII Atomic number 9 corresponds to fluorine, which is in Group VII (Group 17).

Which two atoms are isotopes?

Q and S Isotopes have same number of protons but different neutrons. Q (6p,7n) and S (6p,8n) both have 6 protons, so they are isotopes.

Which of the following statements is correct?

A mixture can contain elements and compounds A mixture is a combination of two or more substances (elements and/or compounds) that are not chemically combined.

Which statement about carbon is correct?

It has 12 nucleons. Carbon-12 has 6 protons and 6 neutrons, so 12 nucleons. Its electron configuration is 2,4, with 2 shells and 4 outer electrons.

Element X contains 12 of each sub-atomic particle. What is the correct Group number for element X?

Group II 12 protons means atomic number 12, which is magnesium. Magnesium has 2 outer electrons, so it is in Group II.

The X⁺ ion of element X has 16 electrons and a nucleon number of 37. What is the correct Group number for element X?

VII X⁺ has lost one electron, so the neutral atom has 17 electrons and therefore 17 protons. Element 17 is chlorine, which is in Group VII.

Which row correctly describes the number of outer shell electrons and properties of isotopes?

Number of electrons: same; Chemical properties: same Isotopes have same number of electrons (same outer shell) so same chemical properties; different neutrons affect physical properties.

Iridium has two isotopes, Ir-191 and Ir-193. Calculate the relative atomic mass of iridium using the data: mass number 191 abundance 62.7%, mass number 193 abundance 37.3%.

191.7 Ar = (62.7×191 + 37.3×193)/100 = (11975.7 + 7198.9)/100 = 19174.6/100 = 191.746 ≈ 191.7.

A selenide ion has the notation ³⁴₇₉Se²⁻. Which row correctly describes the subatomic particles in a selenide ion?

Protons: 34, Neutrons: 45, Electrons: 36 Atomic number 34 = protons. Neutrons = 79-34 = 45. 2- charge means 2 extra electrons, so electrons = 34+2 = 36.

A sample of neon consists of three isotopes: Ne-20 (90.9%), Ne-21 (0.3%), and Ne-22 (8.8%). What is the relative atomic mass of neon to one decimal place?

20.2 Relative atomic mass = (90.9×20 + 0.3×21 + 8.8×22) / 100 = (1818 + 6.3 + 193.6) / 100 = 2017.9 / 100 = 20.179 ≈ 20.2.

An atom of element X has an electronic configuration of 2,8,6. Which group of the Periodic Table does element X belong to?

Group VI The number of electrons in the outer shell (6) indicates the group number for Groups I to VII. Element X is in Group VI.

Copper has two isotopes: Cu-63 and Cu-65. The relative abundance of Cu-63 is 69%. What is the relative atomic mass of copper?

63.6 Relative atomic mass = (69×63 + 31×65) / 100 = (4347 + 2015) / 100 = 6362 / 100 = 63.62 ≈ 63.6.

Which statement about isotopes is correct?

Isotopes have the same number of protons but different numbers of neutrons. Isotopes are atoms of the same element with the same number of protons but different numbers of neutrons.

The relative atomic mass of chlorine is 35.5. Which statement explains this value?

Chlorine exists as two isotopes with different masses, and their average is 35.5. The relative atomic mass is an average of the masses of the isotopes, weighted by their abundances. Chlorine has isotopes Cl-35 and Cl-37, giving an average of 35.5.

A sample of rubidium contains two isotopes: Rb-85 (72%) and Rb-87 (28%). Calculate the relative atomic mass of rubidium to one decimal place.

85.6 Relative atomic mass = (72×85 + 28×87) / 100 = (6120 + 2436) / 100 = 8556 / 100 = 85.56 ≈ 85.6.

How would you design the inquiry for periodic patterns and electron arrangements?

Use a teacher-provided dataset to compare the electron arrangements and properties of elements in a period. Compare the element being compared; record the electron arrangement and chemical properties; compare atoms in their neutral state.

What limitation matters when applying periodic patterns and electron arrangements?

A simple shell model predicts many trends but does not describe the full behaviour of electrons.

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