True or false?

an exothermic reaction could be written as:
heat + a + b > ab

False,the given representation of an exothermic reaction is wrong.

Explanation:

Exothermic reaction are those reaction which releases energy in the form of heat into their surroundings. This release of energy leads to rise in temperature of the of surrounding.

Endothermic reaction are those reaction which energy is absorbed from the surroundings. This absorption of energy leads to lowering in temperature of the of surrounding.

explanation:

let the different atoms be x and y. each with four protons and same mass will be represented as follows.

mass number is number of protons + number of neutrons.

            and  

since, it is given that one has a negative charge while the other is neutral. therefore, there will be increase in number of protons and the atom will be represented as follows.

according to periodic table, mass number of beryllium is 9 and it has atomic number 4 so, the atoms will be and .  

the protons and neutrons will be located inside the nucleus whereas the electrons will be revolving around the nucleus.