Anatomy and Physiology Ch.2 (exam 1)

All forms are composed of chemical elements

Positively charged. in nucleus

Neutrally charged, in nucleus.

Negatively charged. outside the nucleus located on the valence shells in the electron cloud.

Number of protons in an element

Sum of protons and neutrons which indicates its weight. always a whole number

the average mass of all naturally occurring isotopes, since this is an average it is not exactly a whole number.

Atoms that have given up or gained an electron in their outer valence shell.written with chemical sign and + or -

Formed when atoms share electrons. ex.H2O, NaCl

The atoms of a molecule are held together by this force of attraction

Weaker bonding, dissolves easily.positively and negatively charged ions are attracted to one another.
ex. salt (NaCl) in water

Positively charged ions that have given up one or more electrons(that are electron donors)

Negatively charged ions that have picked up one more more electrons that another atoms has lost

Strong bond. hard to pull apart.formed by the atoms of molecules sharing one, two, or three pairs of their valence electrons.most common in the human bodyhas single, double, and triple bonds.may be polar or nonpolar

Likes water. NaCl is an example