Question

I want to learn about increasing and decreasing, who have higher and who have less if we have four choices. Please show like what to do for this type of questions.

Electronegativity

Size of atom

Which molecules are polar and non-polar

Atomic radius

Ionization energy

Answer 1

electronegativity: check the position of the position of the element in the periodic table. the elements which are extreme right that is upto halogen group will have more electronegativity. as we move along the period from left to right, the electronegativity increases. whereas in the group from top to bottom, electronegativity decreases.

SIZE OF THE ATOM: check for the position of the element in the periodic table. The atomic size decreases along the period from left to right, the atomic number increases but the electron enters into same subshell thus the effective nuclear charge increases that is the nucleus attracts the outermost electron strongly, hence the size decreases. Whereas in the group from top to bottom, the size of atom increases, because the electron enters into next higher subshell and effective nuclear charge decreases and thus size increases.

ATOMIC RADIUS: it is the distance from the nucleus to the outermost electron. as we move along period, the atomic radius decreases and along the group the atomic radius increases. it also depends on the effective nuclear charge as like size of atom.

IONIZATION ENERGY: the ionization energy is the energy required to remove an electron from the outermost orbital of a gaseous atom. it depends on size, shielding effect of electrons and half filled or completely filled subshells.
as the size decreases along the period, the ionization energy increases. along the group, size increases and thus ionization energy decreases.
the shielding effect of elctrons is in the order s>p>d>f. hence, the effective nuclear charge on the outermost electron decreases. and thus ionization energy required is less.

it is difficult to remove an electron from the atom which has half-filled or completely filled outermost subshell.