Question

1.Which best explains why ionization energy tends to decrease from the top to the bottom of a group?

Answer 1

1.Which best explains why ionization energy tends to decrease from the top to the bottom of a group?

D.Electrons get farther from the nucleus. They experience a weaker attraction to the positive charge of the nucleus.

3.When electrons are removed from the outermost shell of a calcium atom, the atom becomes

D. a cation that has a smaller radius than the atom. Since the atom is losing an electron, it not only becomes positively charged, also the effective nuclear charge diminishes making the remaining electrons aproach the nucleus.

Answer 2

Answer:

1) Electrons get farther from the nucleus.

2) a cation that has a smaller radius than the atom.

Explanation:

1) ionization energy is the energy required to remove the valence electron from an isolated gaseous atom of an element.

Thus it requires some energy to remove the electron as electrons are attracted towards nucleus (positive protons are present) due to nuclear charge.

As the size increases on moving top to bottom (due to more number of shells) the distance of electrons from the nucleus increases which decreases the effective nuclear charge on electrons, decreasing the ionization energy.

2) When an atom loses an electron it attains a positive charge and is known as cation.

A cation has smaller size than the neutral atom as the less electrons are attracted towards nucleus and thus feel more effective nuclear charge.