Answer : Option C) Four.
Explanation : Valency is defined as the combining power of any element, which is majorly measured by the number of hydrogen atoms that can be displaced or combined with. Also, in short it can be stated as the number of electrons needed in the outermost valence shell of an atom to attain an octet state.
Boron has atomic number 5; where the 5 electrons are present gets arranged in the first shell having 2 electrons and the second shell has 3 electrons. So, the valency of Boron is +3. As it is easy to donate 3 electrons than to get 5 electrons and attain an octet state. So, the group members of the boron family would follow the same trend in terms of valency.
In carbon, the atomic number is 6; it has 2 electrons in the first shell and 4 electrons in the outermost shell. So, the valency of carbon is 6. It can either donate or accept electrons to attain the octet state. Therefore, the members belonging to carbon group family will have valency as 4.
Answer : The correct option is C.
Explanation :
In a periodic table, the elements in each group have the same number of electrons in outermost shell and those outermost electrons are known as valence electrons.
Number of valence electrons = the ones place of the group number
The boron family belongs to group 13 and it has 3 valence electrons.
The carbon family belongs to group 14 and it has 4 valence electrons.
The electronic configuration of carbon is [tex]1s^22s^22p^2[/tex].
