Chemistry Regents Exam Review HW 1 (Atomic Concepts)

What are the three tiny particles that form everything in the universe?

• Proton, Neutron, Electron

• Atom, Molecule, Ion

• Quark, Lepton, Boson

• Nucleus, Electron, Ion

Who provided the mathematical proof for the existence of atoms?

• Marie Curie

• Niels Bohr

• Albert Einstein

• Isaac Newton

What does the atomic number of an element represent?

• Total number of nucleons

• Number of electrons

• Number of neutrons

• Number of protons

Why are neutrons important in an atom's nucleus?

• They act as a buffer between protons

• They determine the atomic number

• They provide charge balance

• They add to the chemical reactivity

What term describes atoms with the same number of protons but different numbers of neutrons?

• Isomers

• Isoelectronic

• Isotopes

• Allotropes

The atomic number represents the number of ...

• protons only

• neutrons only

• protons and neutrons

• neither protons nor neutrons