Atoms, Elements, Molecules, and Compounds. Flashcards
Atom
The smallest particle of an element that can exist.
Element
A pure chemical substance that cannot be physically split into more simple substance. Each is made of one type of atom. Carbon, mercury, and hydrogen are examples.
Molecule
The smallest particle of a substance that can exist. It is composed of two or more atoms.
Compound
A substance made of atoms from two or more elements.
Proton
A particle of matter that has a positive electrical charge and found in the nucleus of an atom.
Neutron
A particle of matter that has no electrical charge and found in the nucleus of an atom.
Electron
A particle of matter that has a negative electrical charge and travels around the nucleus of an atom.
Atomic number
= The number of protons in an element’s atoms. Top number in the element box.
Mass number
Number of protons plus neutrons. Bottom number in the element box.
Chemical symbol
A one or two letter representation of an element.
Subscript
TIny number to the right of the element symbol. Tells you how many atoms of that element.