Work through the list without notes. If you cannot do a statement, follow its link, then come back. Guide = study guide; Practice = practice questions.
Understanding
- I can state the number of valence electrons of any main-group element from its group number. (Guide: “Why valence electrons control chemistry”)
- I can explain how the attraction between nuclei and valence electrons decides whether two elements form an ionic bond, share electrons or do not bond. (Guide; Practice Q7)
- I can explain why elements in the same group form analogous compounds. (Guide: “Same group, same kind of compound”; Practice Q2)
- I can explain, without saying “atoms want a full shell”, why Mg forms Mg²⁺ and not Mg³⁺. (Guide: Figure 2 and Worked example 2)
Skills
- I can predict the typical ion charge for groups 1, 2, 13, 15, 16 and 17. (Guide: Figure 1; Practice Q1)
- I can write an ionic formula as the smallest whole-number ratio and check that the charges add to zero. (Guide: Worked example 1; Practice Q1)
- I can predict a formula from an analogous compound, such as Rb₂Se from Li₂O. (Practice Q2, Q5)
- I can find the number of valence electrons from successive ionization energies and use it to write formulas. (Guide: Worked example 2; Practice Q4)
- I can combine an analogous formula with a molar-mass calculation to identify an unknown metal. (Practice Q5)
- I can write the equation for an element’s reaction by analogy with a group partner, such as K or Ba with water. (Guide: Worked example 3; Practice Q6)
Reasoning
- I can explain why group 1 and group 2 metals become more reactive down the group, using distance and shielding. (Guide: Worked example 3; Practice Q6)
- I can explain why halogens become less reactive down the group. (Guide: “Reactivity and periodicity”; Practice Q3)
- I can correct the claim that more protons means stronger attraction for valence electrons. (Practice Q6(c))
- I can link an observation, such as how violently a metal reacts with water, to a particle-level model. (Guide: Worked example 3)
All ticked? You have finished this unit. Move on to Unit 2, Compound Structure and Properties, starting with Topic 2.1, Types of Chemical Bonds, or return to the course roadmap.