Define the term: electron.

• A subatomic particle with a negative electric charge, found in all atoms and acting as the primary carrier of electricity in solids.

• A positively charged particle found in the nucleus of an atom.

• A neutral particle found in the nucleus of an atom.

• A molecule that forms the basic unit of chemical compounds.

Define the term: nucleus.

• The central part of an atom, containing protons and neutrons.

• A negatively charged particle found outside the atom's center.

• The smallest unit of a chemical element.

• A type of chemical bond between atoms.

Define the term: proton.

• A subatomic particle with a positive electric charge, found in the nucleus of an atom.

• A subatomic particle with a negative electric charge, found outside the nucleus.

• A neutral particle found in the nucleus of an atom.

• A molecule that forms the basis of proteins.

Define the term: neutron.

• A subatomic particle with no electric charge, found in the nucleus of an atom.

• A subatomic particle with a positive charge, found in the nucleus of an atom.

• A subatomic particle with a negative charge, found outside the nucleus of an atom.

• A molecule that forms the basic unit of chemical compounds.

Define the term: atomic number.

• The number of protons in the nucleus of an atom, which determines the chemical properties of an element and its place in the periodic table.

• The number of neutrons in the nucleus of an atom, which determines the isotope of an element.

• The total number of electrons in an atom, which determines its reactivity.

• The sum of protons and neutrons in the nucleus of an atom, which determines the atomic mass.

Define the term: mass number.

• The total number of protons and neutrons in the nucleus of an atom.

• The number of electrons in the outer shell of an atom.

• The total number of protons in the nucleus of an atom.

• The atomic weight of an atom measured in grams.

Define the term: isotope.

• Atoms of the same element that have different numbers of neutrons.

• Atoms of different elements that have the same number of protons.

• Atoms of the same element that have the same number of neutrons.

• Atoms of different elements that have different numbers of electrons.

Define the term: unified atomic mass unit.

• A unit of mass used to express atomic and molecular weights, equal to one twelfth of the mass of an atom of carbon-12.

• A unit of length used to measure atomic radii.

• A unit of energy used to express the binding energy of nuclei.

• A unit of volume used to measure the size of molecules.

Define the term: mole.

• The SI base unit used to measure the amount of a substance, equal to 6.022 x 10^23 particles.

• A unit of mass equal to one thousandth of a kilogram.

• A device used to measure temperature.

• A type of chemical bond between atoms.

Define the term: orbital.

• A region in an atom where there is a high probability of finding electrons.

• A type of chemical bond between atoms.

• A particle found in the nucleus of an atom.

• A force that holds atoms together in a molecule.