sorry i know witch one it is but i could never find the name of it.
i think its Hydrogen
For example caesium and fluorine.
Elements in the same family, or group, have similar physical and chemical properties.
It is supposed that ununtrium is similar to thallium.
No; each chemical element has different properties.
The two elements that have the most similar chemical properties to arsenic are Phosphorus (P) and Antimony (Sb).
Dobereiner was responsible for grouping element into triads. He grouped 3 element with same properties together.
Buttholes
Elements in the same family, or group, have similar physical and chemical properties.
The element that would have properties most similar to the new element would be an element that lies in the same group as the new element. Specifically, the element with the most similar properties will lie directly above or below that element in the group.
Lanthanides have properties similar to Cerium
Selenium.
It has similar properties to the element with proton number 20, which is calcium.
Fluorine or Bromine have similar properties to chlorine because both are halogens.
Only caesium has the same properties as caesium. There are other elements which have some similar properties.
Gggg
It is supposed that ununtrium is similar to thallium.
Elements present within a same group normally have similar properties
Silicon.