atoms and molecules

Front

Define element and list the four elements.

Back

An element is a pure substance composed of only one type of atom. Important elements in the human body include hydrogen, carbon, nitrogen, and oxygen.

Front

What are the three states of matter?

Back

Solid, liquid, and gas.

Front

Describe the structure of an atom.

Back

Atoms are the smallest components of an element that retain the properties of that element, consisting of protons, neutrons, and electrons.

Front

What is the charge and mass of protons?

Back

Protons have a positive charge and a mass of 1 (located in the nucleus).

Front

What is the charge and mass of neutrons?

Back

Neutrons have a neutral charge and a mass of 1 (located in the nucleus).

Front

What is the charge and mass of electrons?

Back

Electrons have a negative charge and no mass (located in orbitals).

Front

What is atomic number?

Back

Atomic number is the number of protons in an atom.

Front

What is atomic weight?

Back

Atomic weight is the total number of particles (protons and neutrons) in the nucleus.

Front

What is a radioisotope?

Back

Radioisotopes are isotopes of an element with an unstable nucleus that emits radioactive decay.

Front

What is atomic stability and reactivity?

Back

An atom is stable and unreactive if its outer electron shell is complete. If not, it can become stable by gaining, losing, or sharing electrons.