The columns going down the periodic table are known as groups or families. Lithium (Li), Sodium (Na), Potassium (K), Rubidium (Rb), Cesium (Cs), and Francium (Fr) are in the same column in the periodic table. Why are these elements in the same column in the periodic table?

They are all together because they are all alkali metals.

Essentially they are silvery and can be cut with a plastic knife.

Their physical properties:

shiny soft silvery highly reactive at standard temperature and pressure readily lose their outermost electron to form cations with a charge of + 1

Their chemical properties:

Alkali metals are highly reactive at standard temperature and pressure and readily lose their outermost electron to form cations with charge + 1. All the discovered alkali metals occur in nature. Most alkali metals have many different applications, such as rubidium and caesium atomic clocks, sodium-vapor lamps, and table salt.