Question

valence shell electrons of first 20 elements

Answer 1

element, valence electrons
H, 1
He, 2
Li, 1
Be, 2
B, 3
C, 4
N, 5
O, 6
F, 7
Ne, 8
Na, 1
Mg, 2
Al,3
Si, 4
P, 5
S, 6
Cl, 7
Ar, 8
K, 1
Ca, 2

I hope it will help you

Answer 2

Hello friend...

VALENCY OF ELEMENTS

1) H. Hydrogen1, 0, -1
2)He. Helium0
3)Li. Lithium1, -1
4)Be. Beryllium2
5)B. Boron3, 2, 1
6)C. Carbon4, 3, 2, 1, -1, -2, -4
7)N. Nitrogen5, 4, 3, 2, 1, 0, -1, -2, -3
8)O. Oxygen2, 1, 0, -1, -2
9)F. Fluorine0, -1
10)Ne. Neon0
11)Na. Sodium1, -1
12)Mg. Magnesium2
13)Al. Aluminum3, 1
14)Si. Silicon4, 3, 2, 1, -1, -2, -4
15)P. Phosphorus5, 4, 3, 2, 1, 0, -1, -2, -3
16)S. Sulfur6, 5, 4, 3, 2, 1, 0, -1, -2
17)Cl. Chlorine6, 5, 4, 3, 2, 1, 0, -1, -2
18)Ar. Argon0
19)K. Potassium1, -1
20)Ca. Calcium 2

Last no. of every element is valency.

Hope this helps you...