atoms, elements, molecuos, and compounds Flashcards
adom
the smallest particle and element to 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 molicus 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 no negative elecrical chage and travels around the nucleus of an atom.
atomic number
= the number of protons in an elements 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.