A&P 2.1 Elements and Atoms- 2.2 Chemical Bonds

Matter

anything that occupies space and has mass

Element

pure substance that is distinguished from all other matter cannot be created or broken down

compound

substance composed of two or more elements by chemical bond

atom

smallest quantity of an element made up of protons, neutrons, electrons

atomic number

number of protons in nucleus of atom

mass number

sum of number of protons and neutrons in nucleus

Isotope

different forms of an element

Radioactive

nucleus readily decays, giving off subatomic particles and electromagnetic energy

Electron Shell

layer of electrons that encircle the nucleus at a distant energy level

Bond

weak/strong chemical attraction that holds atoms in the same vicinity

molecule

two or more groups of atoms

compound

molecules that are made up of 2 or more atoms of different elements

cation

positively charged

anion

negatively charged

ionic bond

ongoing, close association between ions of opposite charge

covalent bond

share electrons in a mutually stabilizing relationship, bounce back and forth between elements

polar covalent bonds

opposite electrical charges

polar molecule

molecule that contains regions that have opposite electrical charges

hydrogen bond

weakly charged positive atom bonded to one electronegative atom