The atom

2. Something that contains only a single type of atom.
4. A group of atoms that are held together by bonds. They act as a single unit.
5. An element that is not a metal. It is not shiny, hard, and a bad conductor of electricity and heat.
8. A horizontal row in the periodic table of the elements.
9. a vertical column in the periodic table of the elements.
10. A material that allows electricity and heat to flow through it.
12. Something that contains two or more different types of atoms bonded together.
13. Anything that has mass (weight) and occupies a space.
16. Atoms of the same element that have a different number of neutrons
17. The number of protons and neutrons in an atom's nucleus.
19. A table of elements, arranged by atomic number that shows patterns in their properties.
20. An element that is usually shiny, easily shaped, and a good conductor of electricity and heat.

1. A particle that has no electric charge and is located in an atom's nucleus.
3. An element that has properties of both metals and nonmetals.
6. A negatively (-) charged particle located outside an atom's nucleus
7. A way that atoms can be connected.
11. The central region of an atom where most of the atom's mass is found. Contains protons and neutrons.
14. The smallest basic unit of matter.
15. A positively (+) charged particle located in an atom's nucleus.
18. The number of protons in an atom's nucleus.