Question

1. the valence electrons in an atom of oxygen in the ground state are all found in the a) first shell b) second shell c) third shell d) fourth shell 4. how many energy levels (or shells) does an atom of gallium (ga) have? a) 3 b) 4 c) 8 d) 18 6. which part of a calcium atom in the ground state is represented by the dots in its lewis electron - dot diagram? a) outermost protons b) inner protons c) inner electrons d) outermost electrons

Explanation:

Step1: Analyze question 2

Oxygen has atomic number 8. Its electron configuration is \(1s^{2}2s^{2}2p^{4}\). Valence electrons are in \(n = 2\) (second shell).

Step2: Analyze question 4

Gallium (\(Ga\)) has atomic number 31. Its electron configuration shows electrons in 4 energy levels (\(n=1,2,3,4\)).

Step3: Analyze question 6

Lewis electron - dot diagrams represent outermost (valence) electrons. Protons are not shown in Lewis diagrams, and inner electrons are not represented by dots.

Answer:

1. B) second shell
2. B) 4
3. D) Outermost electrons