Question

Consider the group 1A elements sodium (period 3), potassium (period 4), and rubidium (period 5). What would you predict about the ionization energies of these elements? Na < K < Rb Na > K > Rb C. Rb < Na < K D. Na = K = Rb

Answer 1

Answer:

B.

Explanation:

Plato

Answer 2

The correct answer is Na > K > Rb.  

The order predicted would be ionization energy of sodium is greater than the ionization energy of potassium, which is greater than the ionization energy of rubidium.  

The ionization energy refers to energy, which has to be supplemented to a gaseous atom in order to withdraw an electron and produce a positive ion. The ionization energy decreases in going down a group. The cause of the decline of the ionization energy down a group is that as one moves down a group, the size of the atom increases that signifies that the valence electrons get further away from the nucleus, and thus, less energy is required to withdraw the electrons.