Question

worksheet 2: valence electrons and ion formation

1. how many valence electrons does each atom have?

a) na b) mg c) al d) cl e) o

1. state whether each atom will lose or gain electrons to form an ion

Explanation:

Step1: Locate group number for each element

Valence electrons match main group numbers (1-2, 13-18: subtract 10 for 13-18).

Step2: Calculate valence electrons for Na

Na is in Group 1: $1$ valence electron

Step3: Calculate valence electrons for Mg

Mg is in Group 2: $2$ valence electrons

Step4: Calculate valence electrons for Al

Al is in Group 13: $13-10=3$ valence electrons

Step5: Calculate valence electrons for Cl

Cl is in Group 17: $17-10=7$ valence electrons

Step6: Calculate valence electrons for O

O is in Group 16: $16-10=6$ valence electrons

Answer:

a) Na: 1 valence electron
b) Mg: 2 valence electrons
c) Al: 3 valence electrons
d) Cl: 7 valence electrons
e) O: 6 valence electrons