Question

1. find the words that are defined in the table below.
2. place the words in the square above.

the smallest unit of an element
a subatomic particle that has a positive charge.
a subatomic particle that has no charge.
a subatomic particle that has a negative charge.
an atom that has become charged by gaining or losing electrons.
atom that has the same number of protons, but different numbers of neutrons.
the numbers of protons in the nucleus of an atom.
the total number of protons and neutrons in the nucleus of an atom.
the part of the atom contains protons and neutrons.
an area around the nucleus where electrons are likely to be found.
greek philosopher who invented the concept of the atom.
scientist who discovered the electron.
scientist who discovered the nucleus of an atom.
scientist who discovered electron energy levels.
one particular type of atom, and it cannot be broken down into a simpler substance.

Explanation:

1. The smallest unit of an element: Atom.
2. A subatomic particle that has a positive charge: Proton.
3. A subatomic particle that has no charge: Neutron.
4. A subatomic particle that has a negative charge: Electron.
5. An atom that has become charged by gaining or losing electrons: Ion.
6. Atom that has the same number of protons, but different numbers of neutrons: Isotope.
7. The number of protons in the nucleus of an atom: Atomic number.
8. The total number of protons and neutrons in the nucleus of an atom: Mass number.
9. The part of the atom contains protons and neutrons: Nucleus.
10. An area around the nucleus where electrons are likely to be found: Electron cloud.
11. Greek philosopher who invented the concept of the atom: Democritus.
12. Scientist who discovered the electron: J.J. Thomson.
13. Scientist who discovered the nucleus of an atom: Ernest Rutherford.
14. Scientist who discovered electron energy levels: Niels Bohr.
15. One particular type of atom, and it cannot be broken down into a simpler substance: Element.

Answer:

1. Atom
2. Proton
3. Neutron
4. Electron
5. Ion
6. Isotope
7. Atomic number
8. Mass number
9. Nucleus
10. Electron cloud
11. Democritus
12. J.J. Thomson
13. Ernest Rutherford
14. Niels Bohr
15. Element