unit 1.1 nature of substances and chemicam reactiona Flashcards
What is the atomic number of an element?
The number of protons in the nucleus of an atom.
What is the mass number of an element?
The total number of protons and neutrons in the nucleus of an atom.
What is an isotope?
Atoms of the same element with different numbers of neutrons.
What is an ion?
An atom or molecule with a net electric charge due to the loss or gain of electrons.
What is an element?
A substance made up of only one type of atom.
What is a compound?
A substance made up of two or more different types of atoms chemically bonded together.
What is a mixture?
A combination of two or more substances that are not chemically bonded.
What is a molecule?
A group of atoms bonded together.
What is a covalent bond?
A chemical bond formed by the sharing of electrons between atoms.
What is an ionic bond?
A chemical bond formed by the transfer of electrons from one atom to another.
What is a chemical formula?
A notation that shows the elements present in a compound and the ratio of atoms.
What is a mole?
A unit of measurement used in chemistry to express amounts of a chemical substance.
What is Avogadro’s number?
The number of atoms or molecules in one mole of a substance, approximately 6.022 x 10^23.
What is a chemical reaction?
A process that rearranges the atoms in one or more substances to produce one or more new substances.
What is an exothermic reaction?
A reaction that releases heat energy to the surroundings.
