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 element box
Chemical symbol
A one or two letter representation of and element
Subscript
Tiny number to the right of the element symbol. Tells you how many atoms of that element