Ch. 6&7 Crosswords

4. the sum of the numbers of protons and neutrons in the nucleus of an atom
5. a horizontal row of elements in the periodic table
6. the number of protons in the nucleus of an atom
8. a unit of mass that shows the mass of an atom or molecule
11. a group in the periodic table that is less reactive than the alkali group and are important compounds for our body
12. a subatomic particle with no charge located in the atom's nucleus
13. one of the elements of group 18 in the periodic table
15. a unique element that has no connections to all the other elements in the periodic table
16. the mass of an mass expressed in atomic mass units
18. an atom that has the same number of protons as the other atoms in the same element but have different number of neutrons

1. one of the elements of group 1 in the periodic table; very reactive
2. a group that is less reactive than both alkali and alkaline-earth metals
3. a vertical column of elements in the periodic table; elements in group shares chemical properties
7. very reactive group in the periodic table that have similar chemical properties, but have different physical properties
9. a pattern in the elements discovered by Dmitri Mendeleev that is later turned into a chart (table)
10. the law that says that the repeating chemical and physical change changes periodically with the atomic numbers of the elements
11. the smallest unit of an element that maintains the properties of that element
14. describes something that occurs or repeats at regular intervals
17. a subatomic particle that has a positive charge and is located in the atom's nucleus