In carbon dioxide, London dispersion forces are the only intermolecular forces of attraction.
a. TRUE
b. FALSE

true

Explanation:

CO has two C-O bonds. The dipoles point in opposite directions, so they cancel each other out. Thus, although CO₂ has polar bonds, it is a nonpolar molecule. Therefore, the only intermolecular forces are London dispersion forces.

m=9

step-by-step explanation:

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.