Question

give the number of valance and core electrons for each. valence electrons are from the group number. core electrons are not valence electrons. it is valence electrons that are gained or lost in a chemical reaction. mg has 9 valence electrons and 10 core electrons mg+2 has 11 valence electrons and 12 core electrons ar has 13 valence electrons and 14 core electrons a. 0 b. 1 c. 2 d. 3 e. 4 f. 5 g. 6 h. 7 i. 8 j. 9 k. 10 l. 11 m. 12 n. 13 o. 14 p. 15 q. 16 r. 17 s. 18 t. 19 u. 20

Explanation:

Step1: Determine Mg valence electrons

Mg is in group 2, so it has 2 valence electrons.

Step2: Determine Mg core electrons

Mg has atomic number 12. Core electrons = 12 - 2 = 10.

Step3: Determine Mg²⁺ valence electrons

Mg²⁺ has lost 2 electrons. So valence electrons = 0.

Step4: Determine Mg²⁺ core electrons

Mg²⁺ has atomic number 12 and has lost 2 electrons, so total electrons = 10. All are core electrons as no valence electrons left, so core electrons = 10.

Step5: Determine Ar valence electrons

Ar is a noble - gas in group 18, so it has 8 valence electrons.

Step6: Determine Ar core electrons

Ar has atomic number 18. Core electrons = 18 - 8 = 10.

Answer:

Mg has C. 2 valence electrons and K. 10 core electrons
Mg⁺² has A. 0 valence electrons and K. 10 core electrons
Ar has I. 8 valence electrons and K. 10 core electrons