Question

answer to 15th question and you will get 20 marks and 1 brainleaster

Answer 1

The number of electrons gained, lost or shared so as to complete the octet of electrons in valence shell is called valency.


Valency of silicon: It has electronic configuration → 2,8.4
Thus, 4 electrons are shared with other atoms to complete the octet and so its valency = 4


Hope it helps u

Answer 2

the combining power of an element especially as measured by the number of hydrogen atoms it can displace or combine with.

the valency is equal to the number of outer most shell of an atom
for example silicon has the following electronic distribution : .. In the outer most shell there are 4 electrons so,the valency of silicon is 4


I hope it helps to you :)