What is Alkaline and acid

Alkaline is a substance that is over the pH of 7. an acid is a substance that is lower than the pH of 7

When universal indicator is put into an alkaline substance it will turn blue/purple/black. If it is an acid the substance will turn red/orange/yellow

The same will happen if litmus paper is used instaed. If the paper turns blue/purple/black it means that the substance is an alkaline. If the paper turns red/orange/yellow it means that the substance is an acid

If the substance or the litmus paper turns green it means that it is neutral (It has the pH of 7)

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vanderwaal's forces of attraction are the electrostatic intermolecular forces that exist in a molecule due to the temporary or permanent dipoles that are developed in a molecule. in , the major intermolecular forces are dipole-dipole interactions as the molecule is polar (bent structure). so the vanderwaal's forces of interaction in between molecules are the permanent dipole-dipole interactions that develop due to the dipole that exists in between the polar h - s bond. the positively charged hydrogen atom is attracted towards the negative end of the dipole that is sulfur of the adjacent molecule. therefore, these forces of attraction are relatively stronger than that of london dispersion forces that exist in non polar molecules.

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.