An ideal gas is one that

a gas whose particles exhibit no attractive interactions whatsoever

a gas whose particles exhibit strong attractive interactions

a gas whose particles exhibit behaviors that closely resemble hydrogen

a gas whose particles exhibit behaviors that closely resemble neon

An ideal gas is one that  a gas whose particles exhibit no attractive interactions whatsoever

Option A

Explanation:

Gas is considered as ideal if the particles present so far away that they do not expose attractive forces to each other. But in reality, there is no ideal gas, but the gas behaves almost perfectly at low pressures and high temperatures (conditions in which individual particles move very fast and far apart, so their interaction is close to zero). That is why the law of ideal gas is such a useful approach. The equation of ideal gas depends on:

                        PV = nRT

Where,

P – pressure in atm or kPa

T – temperature in Kelvin

n – Number of moles of gas

V – volume in litres

R – gas constant (8.3145 J/mol/K)

An ideal gas does not show attractive force between the particles.  In the equation, volume and pressures are directly proportionate to temperature.

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.