According to the Bronsted-Lowry definition,

an acid is a proton acceptor

a base is a proton donor

a base produces H+ ions in aqueous solutions

a base is a proton acceptor

The correct answer is 'a base is a proton acceptor .'

Explanation:

According to the Bronsted-Lowry conjugate acid-base theory:

        Acid → + Conjugate base

       Base + →  Conjugate acid

According to the question the correct answer is 'a base is a proton acceptor.

b. th3 n4zc4 pl4t3 15 c0nv3rg1ng w1th the s0uth 4m3ric4n pl4t3.

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.