Covalent bonds do not gain or lose electrons, but rather share electrons.
Polonium lose electrons.
sn lose 4 electrons
Sodium lose electrons becoming a cation.
Chlorine gain electrons.
All atoms become positive ions when they lose electrons, and negative when they gain electrons.
lose three electrons
No. Atoms can gain and lose electrons but seldom gain or lose protons.
Boron looses three electrons when reacting to nonmetals like oxygen: B --> B3+ + 3e- . Another, less clear, behaviour is shown when boranes, hydrides etc. are formed.
It needs to gain 3 electrons than to lose 5 electrons. So phosphorus has to gain 3 electrons.
Covalent bonds do not gain or lose electrons, but rather share electrons.
Lose
When atoms lose or gain electrons, they form ions. These are charged particles.
Se will gain electrons
In phosphene it gain 4 electrons. Phosphate lose 4 electrons
Lose electrons is oxidation. To gain electrons is reduction.
If you mean Metals... No, they do not gain electrons, they actually lose electrons because it is a lot easy for them to lose them so they can gain stability much faster.