Atomic Structure and Periodic Table

5. The smallest part of a chemical element that can exist
7. An element or substance that is not metal
9. A substance or matter in a state which it will expand freely to fill the whole space without having a fixed shape and volume.
10. The time taken for radioactivity of a specified isotope to fall to half its original value
13. A particle smaller than an atom such as neutrons or a cluster of particles like alpha particles
15. A subatomic particle with a negative electric charge which is found in all atoms and accounts as the primary carrier of electricity in solids.
16. occurs in an atomic nuclei with a positive electric charge,
17. The theory that all matter is made up of atoms
19. The emission of ionizing radiation or particles caused by the spontaneous disintegration of atomic nuclei

1. A reactive non-metallic element that forms strong acidic compounds with hydrogen from simple salts that can be made
2. An element whose properties are between those of metals and solid non-metals or semiconductors.
3. two or more forms of the same element that contain an equal amount of protons but different amounts of electrons within their nuclei,
4. Any of the gaseous elements helium, neon, krypton, xenon and radon occupying group 0 of the periodic table
6. A subatomic particle of the same mass as a proton, but has no electric charge, occurs in all atomic nuclei except ordinary hydrogen.
8. Any substance that has mass which occupies a space by having volume
11. The total number of protons and neutrons within a nucleus
12. A solid material which is typically hard, shiny, malleable, fusible and has good electrical and thermal conductivity.
14. The determination of the age or date of an organic matter from the relative proportions of carbon isotopes carbon-12 carbon-14 that it contains.
18. The number of protons in the nucleus of an atom, which is characteristic of a chemical element and determines its place in the periodic table