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 a 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 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.