Question

1. identify the number of valence electrons.
2. put a check mark in the box to identify which elements will gain electrons and which will lose electrons.

acids and bases
bohr model # of valence electrons will give away (lose) valence electrons will add (gain) extra electrons

Explanation:

Step1: Determine valence electrons for third element

For a neutral atom, the number of valence electrons can be determined from its position in the periodic table or from its electron - shell configuration. Let's assume the third element is sodium (Na). Sodium has an atomic number of 11. Its electron - shell configuration is 2, 8, 1. So the number of valence electrons is 1.

Step2: Determine electron - losing/gaining behavior for third element

Sodium is a metal. Metals tend to lose their valence electrons to achieve a stable electron configuration. So sodium will give away (lose) its 1 valence electron.

Step3: Determine valence electrons for fourth element

Let's assume the fourth element is chlorine (Cl). Chlorine has an atomic number of 17. Its electron - shell configuration is 2, 8, 7. So the number of valence electrons is 7.

Step4: Determine electron - losing/gaining behavior for fourth element

Chlorine is a non - metal. Non - metals tend to gain electrons to achieve a stable electron configuration. So chlorine will add (gain) 1 extra electron to complete its outer shell.

Bohr Model	# of valence electrons	Will give away (lose) valence electrons	Will add (gain) extra electrons
O (shown)	6		√
Na (assumed third)	1	√
Cl (assumed fourth)	7		√

Answer:

Bohr Model	# of valence electrons	Will give away (lose) valence electrons	Will add (gain) extra electrons
O	6		√
Na	1	√
Cl	7		√