Introduction to Chemistry
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The universe consists of _______________ and _________________
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Energy – capacity to do _____________
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Matter- has mass and takes up ___________
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Atom – ________________ unit of a chemical element
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Chemical ELEMENT – a substance that cannot be ________________ down into any other substance.
Parts of the Atom: Center of every atom is a ________________ core called a ________________.
Two parts of a nucleus:
1. Proton* – ________________ charge
2. Neutron* – ________________ (no charge)
* Both have approximately the same mass and are inside the nucleus.
3. Electron – ________________ charge outside nucleus.
Label picture
*__________ charges attract! This holds electrons in their orbital.
 When atoms have ________________ # of protons and electrons …this means they are electrically
________________ no charge
 The key difference between the atoms of different elements is the number of _____________ they
contain. The _______________ NUMBER describes how many protons they have.
 Ex: oxygen:___ protons (in nucleus)
 Ex: Gold atom, by contrast, has ___ protons
 ATOMIC MASS (AKA Atomic weight) is the number of protons AND ______________ in an atom.
HOMEWORK: Choose 5
additional elements and
write their atomic number,
number of protons,
number of neutrons,
number of electrons, and
the atomic mass. Then
draw an atom of each of
those elements. Use
different colors/symbols
for the sub atomic
particles. (include a legend)
GENERIC ATOM MODEL
HYDROGEN
CARBON
OXYGEN
Rules of drawing atoms:
place protons and neutrons in the nucleus
first electron ring/shell holds up to 2 electrons
second – fourth electron ring/shell holds up to 8 electrons
ISOTOPE: When an atom has a _________________ (more or less) number of neutrons.
Example: Carbon 12, 13, and 14.
Bonds and Compounds
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92 different chemical
elements
(________________),
20 artificially produced
(________________)
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Atoms link up w/ each other in different arrangements and combinations.
Chemical bond – a substance that is formed by the ________________ of atoms in definite proportions.
Why do atoms form bonds?
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Answer- due to the arrangement of atoms’ ________________.
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Bonding can occur two ways:
electrons are ________________ or ________________
Shared and transferred electrons serve to bond atoms ______________________!
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Stable atoms are ___________ and outer ring is ___________. These atoms don’t tend to form ________.
Ionic Bonds
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Ion- ________________ particle formed by an atom that has gained or lost one or more of its __________
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Ionic bond – strong ________________ between oppositely charged ions. Transfer of Electrons!
Ex: sodium chloride (________________)
Using the following atoms, show how they would bond ionically.
EX: Magnesium(Mg) and Oxygen (O)
EX: Calcium (Ca) and 2 Chlorines (Cl)
Covalent Bonds

Covalent bond- electrons are ________________ between two atoms.
Ex: Oxygen gas
Using the following examples show how these atoms would bond covalently.
EX: 1 Carbon (C) and 4 Hydrogens (H)

EX: 1 Oxygen (O) and 2 Hydrogens (H)
Bond strength- Single bond (2 e- ), double bond(4 e-) and triple bonds(6 e-)
o The more electrons in the covalent bond, the more strongly the two atoms are joined.
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Examples: H2, O2, and N2
Molecule – ________________ of atoms united by covalent bonds (strong)
 A molecule can have 2 atoms or millions.
Ex: ________________ made of millions of atoms
Ex: ________________ molecule – contains only 3 atoms
Chemical Formulas- They indicate the elements that form the compound and the ________________ in which
they combine. Chemical formulas also indicate the ________________ of each atom in the molecule
Ex: Sodium chloride: _________
1 Sodium chloride ion (Na) for every 1 chloride ion (Cl )
Ex: Glucose: ____________ 6 carbons, 12 hydrogens, and 6 oxygens
pH Scale – (potential Hydrogen ion) A ________________ system that indicated the relative concentrations of
________________ ______.
 The pH scale ranges from ____ to ____
• The difference between consecutive numbers on the scale is actually a difference of 10 times the relative
________________ of the acids or bases. (logarithmic, aka ‘base 10’)
pH Scale
Increasingly Basic
• Closer to 1: ____________
(Lower concentration of H+)
• Closer to 14: ____________
• Closer to 7: ____________
Increasingly Acidic
(Higher concentration of H+)
 Acid – A chemical compound that
________________ H+ ions to solutions
Ex: HCl  H+ + Cl (Higher concentration of H+, Lower concentration of OH-)
 Base (or alkali) – is a compound that ________________ H+ ions and removes them from solution
Ex: Na + O + H+  NaOH (Lower concentration of H+, Higher concentration of OH-)
Research the 6 properties of WATER. You will make a poster in class with your group and you are responsible for
the material on the test.
PROPERTIES OF WATER
1.
2.
3.
4.
5.
6.
Make flashcards for the following terms. Remember to use your own words; 5-6 words or less
CHEMISTRY Vocabulary:
covalent bond
ionic bond
ACID AND BASE Vocabulary:
pH scale
acids
bases
H+
OHion
WATER and its Properties Vocabulary:
polar
hydrogen bond
evaporation
solute
solvent
solution
cohesion
adhesion