Page 1
Name
Chemistry 2
Standard Set 2 deals with two distinct topics: chemical bonds and intermolecular attractive forces, such as hydrogen bonds. A logical
place to begin the study of this standard is with a discussion of the chemical bond. A key point to emphasize is that when atoms of two
different elements join to form a covalent bond, energy is almost always released. Conversely, breaking bonds always requires the
addition of energy. Students should understand that the sum of these two processes determines the net energy released or absorbed in a
chemical reaction.
This standard set requires a basic knowledge of electrostatics and electro-negativity and a thorough knowledge of the periodic
table. After studying standards for chemistry for the elementary grades, students should know that matter is made of atoms and that
atoms combine to form molecules. Students can also be expected to know that atoms consist of protons, neutrons, and electrons.
Although knowledge of complex mathematics is not required for this standard, some background in three-dimensional geometry will
be helpful.
CH 2. Biological, chemical, and physical properties of matter result from the ability of atoms to form bonds from electrostatic
forces between electrons and protons and between atoms and molecules. As a basis for understanding this concept:
Standard
CH 2. a. Students know atoms combine to form molecules by sharing electrons to form covalent or metallic bonds or by exchanging
electrons to form ionic bonds.
Framework
In the localized electron model, a covalent bond appears as a shared pair of electrons contained in a region of overlap between two
atomic orbitals. Atoms (usually nonmetals) of similar electronegativities can form covalent bonds to become molecules. In a covalent
bond, therefore, bonding electron pairs are localized in the region between the bonded atoms. In metals valence electrons are not
localized to individual atoms but are free to move to temporarily occupy vacant orbitals on adjacent metal atoms. For this reason
metals conduct electricity well.
When an electron from an atom with low electronegativity (e.g., a metal) is removed by another atom with high electronegativity (e.g.,
a nonmetal), the two atoms become oppositely charged ions that attract each other, resulting in an ionic bond. Chemical bonds
between atoms can be almost entirely covalent, almost entirely ionic, or in between these two extremes. The triple bond in nitrogen
molecules (N2) is nearly 100 percent covalent. A salt such as sodium chloride (NaCl) has bonds that are nearly completely ionic.
However, the electrons in gaseous hydrogen chloride are shared somewhat unevenly between the two atoms. This kind of bond is
called polar covalent.
(Note that elements in groups 1, 2, 16, and 17 in the periodic table usually gain or lose electrons through the formation of either ionic
or covalent bonds, resulting in eight outer shell electrons. This behavior is sometimes described as “the octet rule.”)
Standard
CH 2. b. Students know chemical bonds between atoms in molecules such as H2, CH4, NH3, H2CCH2, N2, Cl2, and many large
biological molecules are covalent.
Framework
Organic and biological molecules consist primarily of carbon, oxygen, hydrogen, and nitrogen. These elements share valence electrons
to form bonds so that the outer electron energy levels of each atom are filled and have electron configurations like those of the nearest
noble gas element. (Noble gases, or inert gases, are in the last column on the right of the periodic table.) For example, nitrogen has one
lone pair and three unpaired electrons and therefore can form covalent bonds with three hydrogen atoms to make four electron pairs
around the nitrogen. Carbon has four unpaired electrons and combines with hydrogen, nitrogen, and oxygen to form covalent bonds
sharing electron pairs.
The great variety of combinations of carbon, nitrogen, oxygen, and hydrogen make it possible, through covalent bond formation, to
have many compounds from just these few elements. Teachers can use ball and stick or gumdrop and toothpick models to explore
possible bonding combinations.
Standard
CH 2. c. Students know salt crystals, such as NaCl, are repeating patterns of positive and negative ions held together by electrostatic
attraction.
Framework
The energy that holds ionic compounds together, called lattice energy, is caused by the electrostatic attraction of cations, which are
positive ions, with anions, which are negative ions. To minimize their energy state, the ions form repeating patterns that reduce the
distance between positive and negative ions and maximize the distance between ions of like charges.
ICS 1 sem2 block 2 Bonding Standards CH 2 a, b, c
Vocabulary
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
Chemical bonds
Intermolecular attractive
forces
Hydrogen bond
Covalent bond
Chemical reaction
Electrostatics
Electro-negativity
matter
atoms
molecules
protons
neutrons
electrons
geometry
2. a.
Covalent bond
metallic bonds
Ionic bonds.
N2
19. NaCl
20. HCl
21. Octet rule
2. b.
22. H2
23. CH4
24. NH3
25. H2CCH2
26. Cl2
27.
28.
29.
30.
31.
32.
33.
34.
35.
36.
Organic molecules
biological molecules
Carbon
Oxygen
Hydrogen
Nitrogen
2. c.
salt crystals
lattice energy
cations
Anions
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
33.
34.
35.
36.
Bond between 2+ elements; forming a new compound / molecules
between neighboring particles: atoms, molecules or ions
attractive interaction of a hydrogen atom with an electronegative atom, such as
nitrogen, oxygen or fluorine
the sharing of pairs of electrons between atoms
two or more particles have an effect upon one another
phenomena / properties of stationary or slow-moving electric charges
the tendency of an atom to attract electrons
all objects with mass
basic building blocks of particles: molecules, compounds
electrically neutral group of 2+ atoms held together by bonds
positively charged part of the atoms, nucleus
neutral charged part of the atoms, nucleus
negatively charged part of the atom, orbiting the nucleus
the study of dimension, size, shape and position of objects
sharing of pairs of electrons between atoms
Delocalized electrons, called conduction electrons, gathered in an "electron sea", and
the positively charged metal ions.
Attraction between two oppositely charged ions. Ionic bonds are formed between a
cation, usually a metal, and anion, nonmetal.
Diatomic Nitrogen gas
Sodium Chloride
Hydrogen Chloride
Combine; each have eight electrons in their valence shells, giving them the same
electronic configuration as a noble gas
molecular hydrogen composed of two hydrogen atoms
methane
Ammonia
Simplest form of an alkene (a hydrocarbon that contains a carbon - carbon double
bond) called ethene or ethylene
Diatomic Chlorine gas
contain carbon-hydrogen bonds, four classes include carbohydrates, proteins, lipids
and nucleic acids
DNA, RNA, cells, proteins…
Atomic number 6, nonmetallic, forms covalent bonds
Atomic number 8, nonmetallic, Chalcogen family
Atomic number 1
Atomic number 7, nonmetallic, 78% of atmosphere
essential for animal life in small quantities, but is harmful to animals and plants in
excess
measure of the strength of bonds in that ionic compound
is an ion with fewer electrons than protons, giving it a positive charge
is an ion with more electrons than protons, giving it a net negative charge
Page 2
Block 2
Chemical Bonds
http://www2.chemistry.msu.edu/faculty/reusch/virttxtjml/intro2.htm
Covalent bonds- Polar like water, Non-polar like diesel fuel, Share electrons
Lewis-dot for CO2
CO2
Lewis Dot Structure- Rules- remember the Cross-hairs and rotate
Ionic bonds- like salt, trades electrons (transfer)
Na + Cl
=
Na Cl
Common Name
Molecular
Formula
Methane
CH4
Ammonia
NH3
Ethane
C2H6
Methyl Alcohol
CH4O
Ethylene
C2H4
Formaldehyde
CH2O
Acetylene
C2H2
Hydrogen Cyanide
CHN
Lewis Formula
Kekulé Formula
Page 3
Handout: Amazing Atoms
1. protons and neutrons
2. positive neutral
3. three
4. four
5. three
6. group 1 so 1
1. protons neutrons electrons
2. protons neutrons
3. electrons
4. positive and negative
5. neutral and positive
6. same
7. balance
8. no
9. different number, neutrons
10. valence
Oxygen 8 16
8
8 8 6
Calcium 20 40 20 20 20 2
Bromine 35 80 35 45 35 7
Potassium 19 39 19 20 19 1
Carbon 6 14-10=4
e +6p
Phosphorus 15 15-10=5
+15p
Nitrogen 7 15-10=5
+7
Oxygen 8 16-10=6
+8
Sodium 11 group 1 so 1
Chlorine 17 needs 1 so -1
2. Sodium its easy to get rid of one
3. Chlorine needs 1 more for 8
4.
+1-1=0
Magnesium 12 +2
Oxygen 8 -2
Mg
O
1. 2
2. Because Mg is in group 2
3. +2-2=0
1. Boron is in group 13
13-10 = 3 … 3 bonds
2. Oxygen is in group 16
16-10 = 6
wants 8 for stability
…so 2 more, this is also the
number of bonds it forms
3.
H O
H
Chlorine only needed one electron
+2-2=0
1. 4
2. 2 it is the same number
3.
4.
5. 4
Brochure
Next two pages
IONIC bonds
Chemical bonding formed
through electrostatic
attraction between two
oppositely charged ions.
Ionic bonds are formed
between a metal and a
nonmetal ion.
1
Name ______________________
Period ______ Date
____________
Block 2
Title Chemical Bonds
COVALENT bonds
Chemical bonding that is
characterized by the sharing
of pairs of electrons
between atoms, and other
covalent bonds. In short,
the stable balance of
attractive and repulsive
forces between atoms when
they share electrons
METALLIC bonds
Electromagnetic interaction
between delocalized
electrons, called conduction
electrons, gathered in an
"electron sea", and the
metallic nuclei within
metals.
Standard
Chemistry 2 a, b, c
Biological, chemical, and
physical properties of matter
result from the ability of atoms
to form bonds from electrostatic
forces between electrons and
protons and between atoms and
molecules. As a basis for
understanding this concept:
CH 2. a. Students know atoms
combine to form molecules by
sharing electrons to form
covalent or metallic bonds or by
exchanging electrons to form
ionic bonds
CH 2. b. Students know
chemical bonds between atoms
in molecules such as H2, CH4,
NH3, H2CCH2, N2, Cl2, and
many large biological
molecules are covalent.
CH 2. c. Students know salt
crystals, such as NaCl, are
repeating patterns of positive
and negative ions held together
by electrostatic attraction.
CH 2. a. atoms to
CH 2. b. chemical bonds
molecules
2 H2(g) + O2(g) → 2 H2O(l) + Energy
Sharing electrons to
form covalent/metallic
bonds
Exchanging electrons to
CH4 + O2 → CO + H2 + H2O
2 NH4Cl + 2 CaO → CaCl2 +
Ca(OH)2 + 2 NH3
form ionic bonds
Ionic compounds-metals and
non-metals
Molecular (covalent)
compounds-nonmetals
H2CCH2
The simplest form of an alkene
a hydrocarbon that contains a
{carbon – carbon} double bond
called ethene or ethylene
Metallic compounds are
between metals and other
Another important
difference between is that an
6 Li + N2 → 2 Li3N
3 Mg + N2 → Mg3N2
ionic compound is a
crystalline solid at standard
temperature and pressure
(STP), where as a molecular
compound can be in a solid,
gas or liquid state at STP.
Cl2 + H2O
HClO
HCl +
CH 2. c. salt crystals NaCl
Repeating patterns of positive
and negative ions held together
by electrostatic attraction.
Page 4
Handout: periodic table
Back side notes page below
Bond types
Ionic Bond
Two oppositely charged ions
bond,
Give and receive electron to
make bonds
Metallic bonding
"Electron sea" and the
positively charged metal ions.
Sharing of "free" electrons
among a metallic bonding ex.
Salts
Covalent bond
Neighboring atoms share
electrons to form a bond neither
atom hold electron tightly
Compounds /
Molecules
Molecules
is an electrically neutral
group of two or more atoms
held together by covalent
chemical bonds
Atoms / Bohr / Ruth
Atom
1 type of nucleus/electron
millions of atoms
Bohr
created the theory of “qua
Compound
Two or more different
atoms bonded. All
compounds are molecules
Rutherford
Gold foil experiment foun
nucleus