Question

Atomic number of element is 19.how can you say the element belong which group and peroid​

Answer 1

Answer:

Let the element be unknown(even though we know it potassium)

Atomic number = No. of electrons present

Electronic Config of the Element= 2 8 8 1

We look at the number of valence electrons in the element and decide it's group number

• Group number shows the no. of electrons( Not directly)
• We do this only for elements upto Calcium
• If the no. of valence electrons = 1 then it's of group 1 ,if it's 2 it's of group 2
• BUT if it's 3 or greater then we add 10 to the no. of valence electrons and it will give the group number
• for eg Boron has valence electrons 3 so we add 10 + 3 = 13 ,therefore it belongs to the 13th group

I Hope you understand now and will do these questions easily from now on.