Alkali Metals
Alkali Metals
Introduction
Alkali metals refer to six elements belonging to the Group IA of the long form of the Modern Periodic Table, viz. Lithium (Li), Sodium (Na), Potassium (K), Rubidium (Rb), Cesium (Cs) and Francium (Fr). Fr is a radioactive element. These elements are called so because they form strongly alkaline oxides and hydroxides.
Electronic Configuration of Alkali Metals
Each of the alkali metals has one electron in their outermost (valence) shell, which is just outside an inert gas core.
Element
Atomic No.
Electronic Structure
Valence Shell Electron
Li
3
He core, 2s1 i.e. 1s22s1
2s1
Na
11
Ne core, 3s1 i.e. 1s22s22p63s1
3s1
K
19
Ar core, 4s1 i.e. 1s22s22p63s23p64s1
4s1
Rb
37
Kr core, 5s1 i.e. 1s22s22p63s23p63d104s24p65s1
5s1
Cs
55
Xe core, 6s1 i.e. 1s22s22p63s23p63d104s24p64d105s25p66s1
6s1
Fr
87
Rn core, 7s1 i.e. 1s22s22p63s23p63d104s24p64d105s25p65d106s26p67s1
7s1
The solitary electron in the outermost shell can be easily removed from the atom and it is the factor that is largely responsible for the chemistry alkali metals.
Physical Properties
1. Physical state: Alkali metals are extremely soft and readily fused. They are highly malleable (can be pressed out into sheets) and ductile (can be drawn into wires). When freshly cut, they have a bright luster which is quickly tarnished as soon as metal comes in contact with atmosphere. 2. Density: The densities of alkali metals are quite low. Li, Na and K are lighter than water. The densities increase with the increase in atomic number from Li to Sc. However, K is lighter than Na. 3. Melting and boiling points: The melting and boiling points of alkali metals are very low, which progressively decrease when we move downward from Li to Cs. 4. Ionization energies: Alkali metals have low ionization energies, which go on decreasing from Li to Cs. 5.
Introduction
Alkali metals refer to six elements belonging to the Group IA of the long form of the Modern Periodic Table, viz. Lithium (Li), Sodium (Na), Potassium (K), Rubidium (Rb), Cesium (Cs) and Francium (Fr). Fr is a radioactive element. These elements are called so because they form strongly alkaline oxides and hydroxides.
Electronic Configuration of Alkali Metals
Each of the alkali metals has one electron in their outermost (valence) shell, which is just outside an inert gas core.
Element
Atomic No.
Electronic Structure
Valence Shell Electron
Li
3
He core, 2s1 i.e. 1s22s1
2s1
Na
11
Ne core, 3s1 i.e. 1s22s22p63s1
3s1
K
19
Ar core, 4s1 i.e. 1s22s22p63s23p64s1
4s1
Rb
37
Kr core, 5s1 i.e. 1s22s22p63s23p63d104s24p65s1
5s1
Cs
55
Xe core, 6s1 i.e. 1s22s22p63s23p63d104s24p64d105s25p66s1
6s1
Fr
87
Rn core, 7s1 i.e. 1s22s22p63s23p63d104s24p64d105s25p65d106s26p67s1
7s1
The solitary electron in the outermost shell can be easily removed from the atom and it is the factor that is largely responsible for the chemistry alkali metals.
Physical Properties
1. Physical state: Alkali metals are extremely soft and readily fused. They are highly malleable (can be pressed out into sheets) and ductile (can be drawn into wires). When freshly cut, they have a bright luster which is quickly tarnished as soon as metal comes in contact with atmosphere. 2. Density: The densities of alkali metals are quite low. Li, Na and K are lighter than water. The densities increase with the increase in atomic number from Li to Sc. However, K is lighter than Na. 3. Melting and boiling points: The melting and boiling points of alkali metals are very low, which progressively decrease when we move downward from Li to Cs. 4. Ionization energies: Alkali metals have low ionization energies, which go on decreasing from Li to Cs. 5.
References: * Madan * Haider * Block et. al.