Chemistry Midterm Review Part 2

2. A combination of two or more substances that are not chemically combined.
8. A bond where electrons are shared unequally creating partial charges.
9. A group of elements in the periodic table often used in electronics and magnets.
10. Substances formed in a chemical reaction.
12. An atom or molecule with an electric charge due to gaining or losing electrons.
13. The total number of protons and neutrons in an atom.
14. A bond where electrons are shared equally between atoms.
16. A pair of electrons not involved in bonding but belonging to one atom.
17. A weak attraction between a hydrogen atom and another atom often in water molecules.
22. A chart that organizes elements by their properties and atomic number.
24. Anything that has mass and takes up space.
27. The meaningful numbers in a measurement.
30. Small numbers in a chemical formula showing the number of atoms of each element.
31. A bond formed between a positive ion (cation) and a negative ion (anion).
33. A bond where electrons are shared among many metal atoms.
34. Substances that start a chemical reaction.
35. A characteristic that can be observed without changing the substance (e.g. color density).
36. A column on the periodic table where elements have similar properties.
37. Matter that has a fixed composition and properties.

1. A formula showing the exact number of atoms of each element in a molecule.
3. How fast a chemical reaction occurs.
4. A row on the periodic table where elements have the same number of energy levels.
5. Matter cannot be created or destroyed in a chemical reaction.
6. A group of atoms bonded together that act as a single ion.
7. Changes that alter the appearance of a substance but not its composition.
11. Elements in the middle of the periodic table with varying properties.
15. Elements in Group 18 of the periodic table; they are very stable and unreactive.
18. A group of atoms bonded together the smallest unit of a compound.
19. A positively charged particle in an atom's nucleus.
20. Characteristics used to describe matter.
21. Electrons in the outermost energy level of an atom important in bonding.
23. Atoms of the same element with different numbers of neutrons.
25. The energy needed to remove an electron from an atom.
26. Elements in Group 17 of the periodic table; they are highly reactive nonmetals.
28. Forces between molecules that determine how they interact.
29. How consistent or repeatable measurements are.
32. The dense central part of an atom that contains protons and neutrons.