A match-head is flammable, but you have to get it up to its ignition temperature first.
A diamond is flammable, but its ignition temperature is astronomical and
totally out of sight.
Answer:
causes a substance to change from a liquid to a solid.
Explanation:
Nuclear i believe because it has nucleus in the sentence and also talk about it
The atomic number of a neutral atom is equal to the number of protons and the number of electrons of the atom. The atomic weight meanwhile is equal to the sum of the number of protons and number of neutrons. In this case, the no.of protons is 19 and the number of neutrons is 40-19 equal to 21.