Chemisty

3. Mass per unit volume; determines whether an object sinks or floats.
7. A positively charged ion formed by losing electrons.
9. Elements found in the center of the periodic table with variable oxidation states.
12. A vertical column in the periodic table with similar chemical properties.
15. The physical forms in which substances exist: solid, liquid, gas, and plasma.
18. A negatively charged particle that orbits the nucleus.
19. The central part of an atom, containing protons and neutrons.
20. The amount of space an object or substance occupies.

1. An electron in the outermost shell of an atom, important for bonding.
2. A change that affects the form of a substance, but not its chemical composition.
4. A positively charged particle found in the nucleus of an atom.
5. Nonreactive elements in Group 18, including helium and neon.
6. A substance formed from the electrostatic attraction between oppositely charged ions.
8. The weighted average mass of all isotopes of an element.
10. A type of matter with a uniform and definite composition.
11. A horizontal row in the periodic table that indicates energy levels.
13. The number of protons in an atom’s nucleus.
14. A region of space where electrons are likely to be found in an atom.
16. A negatively charged ion formed by gaining electrons.
17. A particle in the nucleus with no electric charge.