Radioactivity comes from unstable atoms of certain elements. Radioactivity consists of alpha radiation (2 protons and 2 neutrons), beta radiation (1 electron), or gamma radiation (Electromagnetic photons).
The smallest particle of such an element is an atom, which consists of electrons centered around a nucleus of protons and neutrons.
<u>Answer:</u> The main group metal produce a basic solution in water and the reaction is 
<u>Explanation:</u>
Main group elements are the elements that are present in s-block and p-block.
The metals that are the main group elements are located in Group IA, Group II A and Group III A.
Oxides are formed when a metal or a non-metal reacts with oxygen molecule. There are two types of oxides which are formed: Acidic oxides and basic oxides.
- Acidic oxides are formed by the non-metals.
- Basic oxides are formed by the metals.
When a metal oxide is reacted with water, it leads to the formation of a base.
The general formula of the oxide formed by Group II-A metals is 'MO'
The chemical equation for the reaction of metal oxide of Group II-A and water follows:

Hence, the main group metal produce a basic solution in water and the reaction is 
"<span>4 Na + O2 2 Na2O" is the one chemical equation among the following choices given in the question that </span><span>is correctly balanced. The correct option among all the options that are given in the question is the fourth option or option "4". I hope that this is the answer that has actually come to your great help.</span>
Answer:
I think 4 but i can't explain how but use the info i know
Explanation:
The electron configuration of an atomic species (neutral or ionic) allows us to understand the shape and energy of its electrons. Many general rules are taken into consideration when assigning the "location" of the electron to its prospective energy state, however these assignments are arbitrary and it is always uncertain as to which electron is being described. Knowing the electron configuration of a species gives us a better understanding of its bonding ability, magnetism and other chemical properties.