Chemistry of Life and Models

Chemistry• An element is

• An atom

A pure chemical substance consisting of one type of atom

The smallest component of an element having the same chemical properties of that element

The Chemistry of Life• Everything is made of elements

• ____ elements occur naturally92

Natural elements in living things•Four elements make up 96% of the mass of a human

•_________________

•_________________

•_________________

•_________________

Carbon C

Hydrogen H

Oxygen O

Nitrogen N

Element symbol

The Chemistry of Life• Six elements that are the main components

of living matter are ______, ______, _______, ______, _________, __________

• Trace elements- elements present in living things in small amounts which controls cell ________

Oxygen CarbonHydrogen Nitrogen Calcium-Ca Phosphorus-P

metabolism

Element used Why it is used

Mammals use

Plants use

iodine For growth, development & chemical activity

magnesium To form chlorophyll in chloroplasts

Fluorine To help teeth resist decay

Atoms: The Building Blocks of Elements

• Both living an nonliving things are made of atoms

• An atom is the smallest particle of an element that has its characteristics

• Structure of an atom

Subatomic particle Symbol Charge Location

proton

neutron

electron

p + nucleus

n 0 nucleus

e - energy levels

electron

neutronprotonnucleus

Periodic Table…

•Is a chart to organize elements

•Has more than ______ elements100

Model of an atomWhich element is shown in this model?

Helium

1

1.0079

H

hydrogen

Example:

Atomic number

Atomic mass

Symbol

Element name

Bohr Model

1. Write the number of p’s and n’s in the nucleus

2. Write the number of electrons in each energy level to complete the model

a. 1st energy level = _____ electrons

b. 2nd energy level = _____ electrons

c. 3rd energy level = _____ electrons

88

2

Example:

Magnesiump =

n =

e =

12

12

12

p=

n=

12

12

Subtract the number of p’s from the atomic mass

E’s in the outermost energy level are called valence electrons

How many valence e’s does magnesium have?

2

Activity- click here for period table

Atomic number- number of protons

Atomic mass- sum of protons plus neutrons