Transcript Location of Subatomic Particles nucleus Protons Neutrons electrons

Atom: basic building blocks of
matter
Structure:
Electron
Proton
Neutron
Nucleus
Definitions:
 Nucleus- center of atom, contains
protons and neutrons
 Protons: positive charge (+)
 Neutrons: neutral charge (=)
 Electrons- negative charge (-), orbit
in energy levels on outside of atom
Location of Subatomic
Particles
electrons
Protons
nucleus
Neutrons

Energy Levels Orbit around nucleus
 Forms “shells” around nucleus
 Electrons fill the shells from the inside
out
1st level: max of 2 electrons
2nd level: max of 8 electrons
3rd level: max of 18 electrons
N
1st
2nd
3rd
Elements: all the same type of
atoms bonded together
Can’t be broken down into simpler
substances
 90 occur naturally
 Others are man-made
 25 essential to living organisms
 99% of living organisms are made of
C,H,O,N

Isotopes- atoms of the same element
with different number of neutrons in the
nucleus
Symbols- shorthand abbreviations for
elements
 Rules:
 First letter always capital
 Second letter always lower case
 Every element has a different
symbol
 Ex’s: Mg N O
Na C
Cl
Periodic Table

Elements are arranged in columns known
as a family or group

Families have similar properties because
the outer shell of the atoms have the same
number of electrons
Atomic Mass on the Periodic
Table
Atomic Number
Symbol
Atomic Mass
11
Na
22.99
Atomic Number & Mass Meanings
Atomic number = the number of protons
and the number of electrons (this will be
equal for stable elements.)
 Atomic mass – the atomic number = the
number of neutrons (round to whole
number)

Molecule/Compound: a
substance that contains different
elements bonded together

Formula- a set of symbols that show the
type of elements and the ratio in which
they combine
 Ex’s: CO2
H2O

Subscript- number after element
indicating the number of atoms present

Coefficient- number in front of the
formula indicating the number of
molecules present
 Ex’s: 3H2O – 3 molecules of water
6NH4 – 6 molecules of
ammonia
Water: (H2O)
One of the most important compounds in
living organisms
 Makes up 70-95% of most organisms

Properties of Water
1. Polar Molecule: it has an unequal
distribution of charge. The oxygen side
has a slightly negative charge, so ionic
compounds dissolve easily in water.
2. Resists temperature change
3. Expands when it freezes
4. High surface tension because the polar
molecules are attracted to each other
and form a slight film on the surface.
5. Capillary action, which means, plants
can carry water up thin tubes.
Organic & Inorganic Molecules
Organic molecules- contain carbon (C)
 Inorganic molecules- do not contain C


Which of the following are organic?
H2O NaCl C6H12O6 CaCO3
Living Organisms are made up of 4
abundant and 9 less abundant elements:
C Hopkins café Magic Salt (NaCl)
*C= carbon
Ca= calcium
*H= hydrogen
Fe= iron
*O= oxygen
Mg= magnesium
P= phosphorus
Na= sodium
K= potassium
Cl= chlorine
I= iodine
*N= nitrogen
*makes up 99.3% of a
S= sulfur
living organism
Bonding

Covalent bond- chemical bond when two
atoms combine sharing electrons
- Examples: sugars, fats, & proteins

Ionic bond- bond formed by the mutual attraction
of two ions of opposite charge

Examples: salt (NaCl) Na+ Cl-
 Hydrogen bond- electrical attraction between a
slightly negative atom and a slightly positive atom.
Very weak so molecules must be close to
experience this attraction.
Examples: water (H2O)
Chemical Equations


Reactants- substances that undergo a
chemical reaction
Products- substances formed by the chemical
reaction
*Chemical equations must be written so they
are balanced! Atoms are neither created nor
destroyed during chemical reactions.