Question

There are 6 electrons in the outermost M-shell of an element. Predict the period and group in the periodic table to which this element may belong.

Answer 1

Step 1:

A systematic arrangement of elements into groups and periods on the basis of similarities in chemical properties and in the order of their increasing atomic number is called modern periodic table.

The horizontal rows of the long form of modern periodic table are called periods. The vertical columns of the long form of modern periodic table are called groups.

The valence shell is the outermost shell of an element. Since the outermost is M-shell, the element belongs to quantum number 3.

Step 2:

The number of valence shell = Number of period

So, the number of period is 3.

The number of valence electrons + 10 = Number of group

So, the number of group is 16.

Quantum numbers	1	2	3
Shell notation	K	L	M
Electrons	2	8	6

There is 6 electrons in the outermost M-shell of Sulphur ($\mathrm{S}$).

Final answer:

Therefore, this element belongs to period 3 and group 16.