Electronic configuration of an atom

Question 1

What do electrons do?

Answer 1

Electrons spin around the nucleus of an atom in a series of levels known as energy shells

Question 2

How are electrons grouped?

Answer 2

They are grouped together in a specific arrangement

Question 3

How can we represent the arrangement of electrons in an atom?

Answer 3

• By writing the electronic configuration

- We can also draw the configuration by using concentric circles around the nucleus

Question 4

How are these shells numbered?

Answer 4

They are numbered according to their distance from the nucleus

Question 5

The shell closest to the nucleus is assigned…

Answer 5

no 1, and the next furthest number, 2

Question 6

How many electrons can each shell hold?

Answer 6

1st shell = 2
2nd or 3rd shell = 8
4th shell = 32

Question 7

Rule no. 1 of drawing/ writing electronic configuration

Answer 7

first, you need to know the no. of electrons in the atom of the element.
This is the same as the no. of protons or the atomic no.

Question 8

Rule no. 2 of drawing/ writing electronic configuration

Answer 8

Electrons will always fill up the shells in order, that is electrons fill up shell 1 and when that is full, they start filling the others

Question 9

Rule no. 3 of drawing/ writing electronic configuration

Answer 9

Crosses/ dots are used to represent the electrons in the shells

Question 10

Example: Lithium

Answer 10

because the atomic # is 3, that means that there are 3 protons, which equals 3 electrons.

Mass # = 7
Atomic # = 3
# of protons= 3
# of electrons= 3
# of neutrons= 4 (mass no. - atomic no.)
Li (2,1)

Question 11

When writing the electronic configuration, How is it written?

Answer 11

The symbol of the elements is written first, followed by the number of electrons in each shell separated by commas eg. Nitrogen= N(2,5)