Transcript Elements, Atoms, and Models

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
• ____
92 elements occur naturally
Natural elements in living things
•Four elements make up 96% of the mass of a
human Element
symbol
Carbon
C
•_________________
Hydrogen H
•_________________
Oxygen
O
•_________________
Nitrogen
N
•_________________
The Chemistry of Life
• Six elements that are the main components
Oxygen ______,
Carbon
of living matter are ______,
Hydrogen ______,
Nitrogen _________,
_______,
__________
Calcium-Ca Phosphorus-P
• Trace elements- elements present in living
things in small amounts which controls cell
________
metabolism
Element used
Mammals use iodine
Plants use magnesium
Fluorine
Why it is used
For growth, development &
chemical activity
To form chlorophyll in chloroplasts
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
p
+
nucleus
neutron
electron
n
0
-
nucleus
e
energy levels
Model of an atom
electron
neutron
proton
nucleus
Which element
is shown in
this model?
Helium
Periodic Table…
•Is a chart to organize elements
100 elements
•Has more than ______
Example:
1
H
1.0079
hydrogen
Atomic
number
Symbol
Atomic
mass
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
2 electrons
a. 1st energy level = _____
8 electrons
b. 2nd energy level = _____
c. 3rd energy level = _____
8 electrons
Example:
p = 12
Magnesium
n = 12
e = 12
Subtract the
number of p’s
from the atomic
mass
E’s in the outermost
energy level are called
valence electrons
p= 12
n= 12
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