Transcript Chemistry

Basha High
School
Chapter 2
Matter
• Everything in the universe is made up of matter,
occupies space and has mass.
• Mass is the amount of matter an object has.
• Mass and weight are not the same, gravity is
what gives an object its weight.
Elements
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1.
2.
3.
4.
Elements are pure substances that cannot be
broken down chemically into simpler kinds of
matter.
More than 100 elements have been identified, but
only 30 are important for life.
90% of the mass of all kinds of living things are
composed of combinations of four elements.
Oxygen, O
Carbon, C
Hydrogen, H
Nitrogen, N
Atoms
• Simplest particle of an
element that retains all of the
properties of that element.
• The properties of different
kinds of atoms determine the
structural properties of the
matter that they compose.
Nucleus
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It consists of two kinds of particles.
Protons have a positive charge
Neutrons have no electrical charge
Most weight of the atom will be found in
the nucleolus.
• All atoms of a given element have the same
number of protons.
• The number of the protons in an atom is
called the atomic number.
• The atomic number of fluorine is 9, which
means that there are 9 protons.
Electrons
• They are high-energy
particles with very little
mass.
• They move about the
nucleus at very high
speeds in one of several
different energy levels.
• There is more energy in
the outer shells than in
the inner shells.
Compounds
•
Most elements readily combine with other
elements.
• The chemical formula shows the make-up of
the bond and what type of particles are in
each make-up.
1. H2O –2-Hydrogen, 1-Oxygen: Water
2. CO2 –1-Carbon, 2-Oxygen: Carbon Dioxide
3. C6H12O6- 6-Carbon, 12-Hydrogen, 6-Oxygen:
Sugar
Covalent Bonds
• These are formed when two atoms share one
or more pairs of electrons.
• Water is made up of one oxygen and two
hydrogen atoms held together by covalent
bonds.
• This is so that the element can achieve
stability.
Water
Ionic Bonds
• This is when the outer shell
is missing an electron.
• Elements will either take
away or give an electron to
form a very tight bond.
• Once the bonding has
occurred it is a very strong
bond that takes a lot of
energy to break apart.
– Example: NaCl AKA. salt
Salt