Question

1) The ionization energy of an atom is the energy required to remove an electron from the atom in the gaseous state.

Arrange the following elements in order of decreasing ionization energy.

molybdenum

silver

germanium

phosphorus

strontium

2)

The metallic character of an element is defined as the properties typical of a metal, especially the tendency to lose electrons in chemical reactions.

Arrange the following elements in order of decreasing metallic character.

F

Cr

P

Zn

Ca

Cs

S

Answer 1

1.

The ionization energy increases across a period but decreases down a group.

In other words, the elements with the lowest ionization energies would be in the bottom left-hand corner of the periodic table. The change in ionization energies is also larger going down the periodic table (by change within a group) than going across the periodic table (by change within a period).

Let's from the bottom of the periodic table:
strontium (Sr), molybdenum (Mo) and silver (Ag) elements is in the lowest period at 6. Since ionization energy increases across a period,

Sr will have lowest ionization energy and Ag will have heighest ionization energy

Sr < Mo < Ag

Now, let's go to the fourth period, where germanium (Ge) is present; third period, where phosphorous (P) is present.

Hence, the decreasing order of ionization energy is as below:

P > Ge > Ag > Mo > Sr

2.

Metallic character increases as you go down the periodic table while it decreases as you go from left to right.

Cs is in 6th period.

In fourth period, where Ca, Cr and Zn are present. Since metallic charecter decreases across a period, so

Ca > Cr > Zn

In third period, where P and S are present. Since metallic charecter decreases across a period, so

P > S

In second period, where F is present.

F

Now, as you move left across period and down the group: increase metallic character, so,

Cs > Ca > Cr > Zn > P > S > F