Question

storyline 1 exam
which list arranges the elements na, li, k, rb, and cs in order of increasing ionization energy (from left to right)?
○ cs, li, na, k, rb
○ cs; rb; k, na; li
○ na, li, k, rb, cs
○ li, na, k, rb, cs

Explanation:

Ionization energy is the energy required to remove an electron from an atom. In a group (vertical column) of the periodic table, ionization energy decreases as we move down the group. This is because as we go down a group, the atomic radius increases. The out - ermost electrons are farther from the nucleus and are more shielded from the nuclear charge.

The elements \(Na\), \(Li\), \(K\), \(Rb\), and \(Cs\) are all in Group 1 (alkali metals). The order of these elements from top to bottom in the group is \(Li\), \(Na\), \(K\), \(Rb\), \(Cs\). Since ionization energy decreases down a group, the order of increasing ionization energy (from lowest to highest) is the reverse order of their position in the group.

Answer:

Cs, Rb, K, Na, Li