Question

answer this fast please,, and sorry for the last question's English my keyboard went wild. ​

Answer 1

Answer:

28

Explanation:

Answer 2

Given- 4 election in outermost shell(n=3).

Neutron=14

we know ,

for n=3

electron present=2+8+8=18.

since 4 electron present in outermost so electron present in atom are 2+8+4=14.

since electron=proton=14.

we know Mass no•= Proton+Neutron

Mass no•=14+14=28.