It’s B then A then C then D
Answer:
Its helium
Explanation: Because teh effective nuclear charge holds the valence ectrons clos to the nuclues. the Atomic radius would decrease as you move from the led=ft and right of the perodic table
An ionic compound is formed by exchange of valency between bonding ions.
The formula of an ionic compound formed from O2− with;
Magnesium ion has a charge of 2+ and oxygen ion has a charge of 2-, when the two are combined, we obtain a compound of formula MgO.
Sodium ion has a charge of +1 and oxygen ion has a charge of 2-, when the two are combined, we obtain a compound of formula Na2O.
Aluminium ion has a charge of +3 and oxygen ion has a charge of -2, when the two are combined, we obtain a compound of formula Al2O3.
Learn more: brainly.com/question/11527546
Explanation:
can u post a picture of the question ?
Answer:
They are atoms that make up a subatomic particle
Explanation:
Atoms are made up of protons, neutrons and electrons, also known as subatomic particles. Because an atom is neutral, the number of electrons is equal to the number of protons. Electrons circle the nucleus, which is made up of protons and neutrons.