Elements, Atoms, & Chemical Bonds

What are the main chemical elements in the body?

Oxygen, Carbon, Hydrogen, and Nitrogen

What percent of our total body mass is Oxygen?

65%

What percent of our total body mass is Carbon?

18.5%

What percent of our total body mass is Hyrdrogen?

9.5%

What percent of our total body mass is Nitrogen?

3.2%

What are atoms?

the smallest units of matter that retain element properties and characteristics

Atomic Number

number of protons in an atom’s nucleus

Mass Number

number of protons and neutrons in an atom

Isotopes

forms of the same chemical element that have the same number of protons but a different number of neutrons

Maximum number of electrons allowed in the innermost shell

2

Maximum number of electrons allowed in shell 2

8

Maximum number of electrons allowed in shell 3

18

Maximum number of electrons allowed in shell 4

32

Ion

an atom that has lost or gained an electron

Molecule

2 or more atoms sharing electrons

Compound

a substance that can be broken down into 2 or more different elements

Name the elements that are seen most often as ions in the body.

Bicarbonate, Calcium, Sodium, Potassium, Chlorine, Hydrogen, and Magnesium

Free Radicals

have an unpaired electron in its outermost shell

Ionic Bonds

bonds formed by the transfer of electrons

Covalent Bond

bond formed when two or more atoms share electrons

Polar Bond

bond formed by an unequal sharing of electrons

Hydrogen Bond

a weak bond formed as a result of partial charges between atoms

Nonpolar Covalent Bonds

atoms share electrons equally, similar electronegativity

Polar Covalent Bonds

atoms don’t share electrons equally, different electronegativity

Antioxidants

inactive oxygen-derived free radicals

What determines an atoms ability to form a chemical bond?

the number of electrons in the valence shell

Cations

positive charged atoms, more protons

Anions

negative charged atoms, more electrons

Water Cohesion

happens when hydrogen bonds between water molecules

Hydrogen Bonds create…

surface tension

Surface Tension

tight, invisible skin on the top of a liquid that holds it together

Inorganic Compounds

usually lack carbon and are simple molecules

Name the most important inorganic compound

Water

Organic compounds

always contain H, usually contain O, and always have covalent bonds