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 hydron are examples.
molecule
the smallest particle of substances that exist. It is composed of 2 or more atoms.
compound
a substance made of atoms from 2 or more elements.
proton
a particle of matter that has a positive electrical charge
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. tell you how many atoms of that element.