Answer:
5. An element's mass number tells the number of protons in its nucleus.
Atomic
6. Negatively charged particles in an atom are called electrons.
True
7. The cloud model of the atom describes the location of electrons as specific orbits around the nucleus.
Bohr
8. Atoms with the same number of protons but different numbers of neutrons are called isomers.
Isotopes
9. The sum of the protons and neutrons in an atom is called the atomic number.
Mass
10. An object that helps explain ideas about the natural world is called a model.
True
11. Mendeleev arranged his periodic table in order of increasing atomic number.
Mass
12. The rows in the periodic table are called periods.
True
13. Moving across the periodic table from left to right, one finds, in order, metals, then gases, then nonmetals.
Metalloids
14. Another name for a period is a family.
Group
15. On the periodic table, elements in the same column have similar properties.
True
Explanation:
