Which statement describes all chemical changes, but not all physical changes? a.) bubbles are produced b.) a new substance forms c.) phase changes occur d.) a color change occurs

B. a new substance forms.

Option (B) is the correct answer.

Explanation:

A chemical change is a change which occurs due to change in chemical composition of a substance.

For example, churning of milk into curd is a chemical change because chemical composition of milk changes as it turns into curd.

Thus, we can conclude that out of the given options the statement a new substance forms describes all chemical changes, but not all physical changes.

clouds form

solid ice forms on leaves.

water droplets form on grass.

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.