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 to 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.