Question

what is the difference in the number of valence electrons for element a and the number of valence electrons for element c? type your answer in the box below.

Explanation:

Step1: Determine valence electrons of A

Element A is in Group 1 (alkali metals, yellow group on left), so valence electrons = 1.

Step2: Determine valence electrons of C

Element C is in Group 17 (halogens, pink - purple transition? Wait, Group 17 (like Cl, F) has 7 valence electrons. Wait, maybe A is Group 1 (1 valence e - ), C is Group 7 (7 valence e - )? Wait, no, maybe A is Group 2? Wait, no, the left - most yellow group: Group 1 (1 valence e - ), red is Group 2 (2 valence e - )? Wait, no, standard periodic table: Group 1 (1), Group 2 (2), then transition metals, then Group 13 (3), 14 (4), 15 (5), 16 (6), 17 (7), 18 (8). Wait, the element A: let's assume A is in Group 1 (1 valence e - ), C is in Group 7 (7 valence e - )? Wait, no, maybe A is Group 1 (1), C is Group 7 (7)? Wait, no, the difference: |1 - 7| = 6? Wait, no, maybe A is Group 2 (2) and C is Group 7 (7)? No, wait, the problem: let's re - evaluate. Wait, element A: left - most yellow column, likely Group 1 (1 valence electron). Element C: in the halogen group (Group 17), 7 valence electrons. So difference: 7 - 1 = 6? Wait, no, wait: valence electrons of A: 1, valence electrons of C: 7. Difference: |7 - 1| = 6? Wait, maybe I got A wrong. Wait, maybe A is Group 2 (2 valence e - )? No, the left - most red is Group 1, yellow is Group 2? Wait, no, standard periodic table: Group 1 (alkali metals, 1 valence e - ), Group 2 (alkaline earth, 2 valence e - ). Then transition metals (blue), then Group 13 (3), 14 (4), 15 (5), 16 (6), 17 (7), 18 (8). So if A is Group 1 (1), C is Group 7 (7), difference is 7 - 1 = 6. If A is Group 2 (2), C is Group 7 (7), difference is 5. But likely A is Group 1 (1), C is Group 7 (7). So 7 - 1 = 6.

Step3: Calculate the difference

Valence electrons of A: 1, Valence electrons of C: 7. Difference: $|7 - 1| = 6$.

Answer:

6