Question

Which of these elements belong to be period 3?
a. 3Li, 14Si, 2He, 11Na, 15P

Which of these elements belong to the second group?
b. 1H, 7N, 20Ca, 16S, 4Be, 18Ar

Which is the most electronegative element among these?
C. 7N, 6C, 80, 5B, 13A1​

Answer 1

Answer:

a- 14Si, 11Na, 15P

b- 20Ca , 4Be

c- 8O

Explanation:

see this in modern periodic table

for c- along period electronegativity increased and hence oxygen is the most electronegative element among these