Give scientific reasons. (Any 2) [4]
1. The weight of a body is different on different planets.
2. Atomic radius goes on increasing down a group.
3. Elements belonging to same group have same valency.
Answers
Answer:
the weight of a body is different on different planets
Answer:
Explanation:
2) (i) Atomic radius is the distance between the centre
of the atom to its outermost shell.
(ii) New shells are added to the atoms of the elements
as we go down from top to bottom in a group.
(iii) The outermost electrons go further and further
away from the nucleus, extending the radius and
ultimately increase in the size of the atom. Hence,
atomic radius goes on increasing down a group.
3) (i) Valency is the number of electrons donated,
accepted or shared by the atoms of an element so
as to complete the octet in the outermost orbit.
(ii) Valency is dependent upon the number of valence
electrons present in the outermost shell of an atom
called valence electrons.
(iii) Elements in the same group have same number
of valence electrons, irrespective of the number
of orbits. Hence, elements in the same group have
the same valency.