Elements Number of protons/ Atomic Number Mass
Number of electrons number of neutrons number
Lithium 3 3 4 7
Carbon 6 6 6 ……
Argon 18 ….. 22 ……
Sulphur 16 …… ……. 32
Answers
Answer:
Carbon - _{\ 6}^{12}\ C
6
12
C
b. Oxygen - _{\ 8}^{16}\ O
8
16
O
c. Phosphorus - _{\ 15}^{31}\ P
15
31
P
d. Argon - _{\ 18}^{40}\ Ar
18
40
Ar
e. Calcium - _{\ 20}^{40}\ Ca
20
40
Ca
The upper number represents the - mass number & the lower number the - atomic number.
Solution :
a. Carbon
Atomic number = 6
Mass Number = 12
No. of protons = 6
No. of electrons = 6
No. of neutrons = 12 - 6 = 6
Electronic configuration - (K, L) = (2, 4)
b. Oxygen
Atomic number = 8
Mass Number = 16
No. of protons = 8
No. of electrons = 8
No. of neutrons = 16 - 8 = 8
Electronic configuration - (K, L) = (2, 6)
c. Phosphorus
Atomic number = 15
Mass Number = 31
No. of protons = 15
No. of electrons = 15
No. of neutrons = 31 - 15 = 16
Electronic configuration - (K, L, M) = (2, 8, 5)
d. Argon
Atomic number = 18
Mass Number = 40
No. of protons = 18
No. of electrons = 18
No. of neutrons = 40 - 18 = 12
Electronic configuration - (K, L, M) = (2, 8, 8)
e. Calcium
Atomic number = 20
Mass Number = 40
No. of protons = 20
No. of electrons = 20
No. of neutrons = 40 - 20 = 20
Electronic configuration - (K, L, M, N) = (2, 8, 8, 2)