Periodic table

3. these can transmit heat, sound, and electricity
4. the most reactive element in group 1
7. the vertical columns on the periodic table that indicate reactivity
9. a particle smaller than an atom, such as a proton, neutron, or electron
11. the most stable group on the periodic table
16. negatively charged particles that orbit the nucleus
17. a property of metals that allows them to be stretched or hammered into a wire
18. the middle of the atom that holds a positive charge and contains protons and neutrons
20. 10 protons
21. metalloid group 3

1. group 1 level of reactivity
2. 19 electrons
5. nonmetal group 4
6. the number of these determines the reactivity of the element; determined by group/family number
8. a nonmetal with 8 protons
10. determined by subtracting the mass number minus the atomic number (MAN)
12. element in group 1 and period 3
13. for protons and neutrons it is 1, for electrons it is less than 1
14. makes up the mass of an atom with neutrons
15. 7 valence electrons and period 5
19. the horizontal rows that indicate the number of energy levels or rings