Which represents a balanced nuclear equation? 7Na —> Mg + H
24 Na
24 mg +
0
>
e
11
12
-1
O A1—34 Mg +
e
o 73
23
12
Mg
> 24 Mgton

c-14 is carbon-14, or radiocarbon.   it is a radioactive isotope of carbon with an atomic nucleus containing 6 protons and 8 neutrons.

1 is the answer to this problem

atomic mass = 39

number of neutrons = 20

number of protons= 19

electronic configuration = 1s2 2s2 2p6 3s2 3p6 4s1

the number of electron in first shell = 2

number of electrons in n=3 shell = 8