Explanation:
The problem here is to find the atomic number of each of the element given.
Sum the powers of the configuration.
a- 1s² 2s² 2p⁶ 3s² 3p⁶ 4s¹
Atomic number is = 2 + 2 + 6 + 2 + 6 + 1 = 19
b- 1s² 2s² 2p⁶ 3s² 3p⁴
Atomic number = 2 + 2 + 6 + 2 + 4 = 16
c- 1s¹
Atomic number = 1
Answer:
Air is a qualified element
Bonjeur monseur, la french are here! it seems you have a problem with the elements on earth. lead seems correct since it is indeed a harmful material
