Chemistry

3. Atoms of the same element that have different numbers of neutrons.
4. the number of protons in the nucleus of an atom, which determines the chemical properties of an element and its place in the periodic table
6. a table of the chemical elements arranged in order of atomic number, usually in rows, so that elements with similar atomic structure and appear in vertical columns.
9. The vertical columns in the periodic table.
10. Attraction formed when elements share electrons.
13. relating to the simplest units of an element or compound
14. A formula that shows what elements are in a compound and what it will become.
17. A chemical element with atomic number 3, symbol Li. It is an alkali metal
20. Force that holds atoms together in a compound

1. Between groups 1 and 2, and 13 and 18.
2. a positively charged ion
5. the simplest structural unit of an element or compound
7. type of linkage formed from the electrostatic attraction between oppositely charged ions in a chemical compound
8. consisting of one atom
11. a group of symbols that make a mathematical statement
12. each of more than one hundred substances that cannot be chemically inter converted or broken down into simpler substances
14. a thing that is composed of two or more separate elements
15. a negatively charged ion
16. the basic unit of a chemical element.
18. relating to, composed of, or using ions
19. Horizontal rows of elements.