Crossword

2. Positive charge
4. Negative charge.
6. Very reactive, electropositive, monovalent metals forming strongly alkaline hydroxides.
7. Element that doesn't have the characteristics of metal.
10. Average of the proton rest mass and the neutron rest mass.
11. Group of chemical elements with very similar properties
13. Loss of elementary particles from an unstable nucleus, ultimately changing the unstable element into another more stable element.
16. Positively charged center of the atom consisting of protons and neutrons.
17. Any of the series of fifteen metallic elements from lanthanum to lutetium in the periodic table.
18. Atom or molecule that has gained or lost one or more of its valence electrons.
19. Any of the elements fluorine, chlorine, bromine, iodine, and astatine, occupying group
21. Each of two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nucleus.
22. An electrically charged atom or group of atoms formed by the loss or gain of one or more electrons.
23. The number of protons in the nucleus of an atom.
24. Region of negative charge surrounding an atomic nucleus that is associated with an atomic orbital

1. A vertical column in the periodic table of the elements.
3. No charge.
5. Any of the set of metallic elements occupying a central block.
8. Any chemical element that is an effective conductor of electricity and heat.
9. Spontaneous emission of radiation in the form of particles or high energy photons resulting from a nuclear reaction.
10. Any of the elements found in Group.
12. Properties are intermediate between those of metals and solid nonmetals or semiconductors.
14. These elements, together with the lanthanides, are called internal transition elements.
15. An electrically charged atom or group of atoms formed by the loss or gain of one or more electrons.
20. A horizontal row in the periodic table of the elements (has varying properties).