Chemistry Elements and Bonds

Chemistry of Life All matter is composed of tiny particles called atoms There are 109 types of atoms A substance made-up of one kind of atom is called an element An atom is the smallest part of an element that still has the properties of that element.

CHNOPS Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorus, and Sulfur aka CHNOPS make up 99% of organic matter

Molecules and Compounds When two or more atoms bond, they form a molecule. A compound is a substance made of 2 or more different elements

In Your Notes… How is it that two atoms can make a molecule but not a compound?

Why do elements bond? Elements bond(stick together) based on the number of their valence electrons (out ring of electrons) Rule of 8 If the outer ring of electrons is not full with 8 total electrons, the atom will bond to complete it’s outer ring. (Hydrogen’s outer ring is full with 2)

Ionic Bonds Formed when atoms lose or gain electrons (trade electrons) and become electrically positive or negative. The resulting opposite charges a drawn to each other.

Covalent Bonds Formed when atoms “share electrons”

Ionic Bond vs. Covalent Bond Atoms gain or lose electrons. Strong Bond Strength Breaks apart in water Atoms share electrons Medium Bond Strength Can single, double, or triple Bond Attraction between 2 or more atoms Caused by incomplete electron shells

A is for Atom Answer the questions on a separate sheet (or ½ sheet) of paper.