Chemistry of Life.

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Chapter 6: The Chemistry of Life

Ch. 6.1 Atoms & Their Interactions

Both living and nonliving things are composed of the same basic building blocks called atoms.


Element- a substance that can't be broken down into simpler chemical substances.

On Earth, 90 elements occur naturally

Natural elements in living things-

Only about 25 of 90 elements are essential to living organisms. Each element is identified by a one or two letter abbreviation ex: C - carbon

Trace elements-

Exist in very small amounts but are essential

Atoms: The building blocks of Elements

Elements are made up of atoms

Atoms- the smallest particle of an element that has the characteristics of that element

The structure of an atom-

Each element has distinct characteristics

Nucleus- center of atom made of positively charged particles (protons) and particles with no charge (neutrons)

Electron cloud- small particles with negative charge spin at high speed around the nucleus

Electron energy levels-

Each energy level has a limited capacity: first holds 2 e-, second holds 8 e-, and third holds 18 e-

Isotopes of an Element-

Isotopes- atoms of the same element that have different numbers of neutrons

ex: Carbon- 12, Carbon- 13, and Carbon- 14

Isotope nuclei are unstable and break apart releasing energy as they do

Compounds & Bonding-

Water is not an element, it is a compound

Compound- a substance that is composed of atoms of two or more different elements that are chemically combined

Characteristics of a compound are different than those of the individual elements

How covalent bonds form-

Most matter is in the form of compounds

Most elements are stable when their outer energy levels are full, one way to fill the outer shell is to share electrons

Most compounds in organisms have covalent bonds

Covalent bonds- the force...