Chemistry
Give reasons for the following:
Atomic size decreases across a period but increases down a group of the periodic table.
Answer
Across a period from left to right, nuclear charge increases. This decreases the size of the atom because the electrons are then attracted towards the nucleus with a greater force thereby bringing the outermost shell closer to the nucleus.
Down a group, the number of shells and nuclear charge both increase. But increase in the number of shells dominate over increase in nuclear charge. This increase in the number of shells increases the size of an atom because the distance between the outermost shell and the nucleus increases.
Related Questions
Give reasons for the following:
Atoms with large atomic radii and low ionization potential are more metallic in nature.
Give reasons for the following:
A decrease in ionization potential of an element leads to a decrease in non-metallic character of the element.
In period 2, element 'A' is to the right of element 'B'
- The element 'A' would probably have a …………… [smaller/larger] atomic size than 'B'.
- The element 'B' would probably have …………… [lower/higher] ionization potential than 'A'.
- The element 'A' would have …………… [lesser/higher] electron affinity than 'B'.
- Nuclear charge of element 'B' would be …………… [less/more] than element 'A'.
- If an element 'C' had a low electronegativity and ionization potential it would have more tendency to …………… [gain/lose] electrons.
With reference to period 3 of the periodic table — State :
- The type of bonding of the element with electronic configuration 2, 8, 7.
- The formula of the chloride of the element with electronic configuration 2, 8, 4.
- The nature of the oxide of the alkaline earth metal in the period.
- The number of electrons in the penultimate shell of the element with valency -1.
- The electronic configuration of the element whose hydroxide is a weak base.