New substances form, color changes, a precipitate forms, gas production, changes in temperature and changes in properties.
What are signs a chemical reaction has taken place?
100
The number of protons in an atom determines this number.
What is the atomic number?
100
Draw a Lewis Dot structure for carbon.
"C" with a dot on each side representing carbon's four valence electrons.
.
. C .
.
100
Na F; valence electrons transfer
What is an ionic bond?
100
An atom that has become electrically charged.
What is an ion?
200
Bonds are broken and new bonds may form.
What happens to chemical bonds during a chemical reaction?
200
protons + neutrons
What is the atomic mass?
200
The number of valence electrons in nitrogen.
What is five?
200
NO2; valence electrons are shared
What is a covalent bond?
200
The name of the rule used for atoms forming bonds when either the number of valence electrons increases to a total of eight, or all the valence electrons are lost.
What is octet rule?
300
This first type of reaction releases energy in the form of heat while the second type absorbs energy and feels cool to the touch.
What are exothermic and endothermic reactions?
300
They explain why the atomic mass is usually a decimal number.
What are isotopes?
300
Type of elements located on the left side of the periodic table. They give electrons during chemical bonding and become positively charged ions.
What are metals?
300
Bonds between two nonmetals are usually this type.
What is a covalent bond?
300
When they form, atoms become more chemically stable.
What are chemicals bonds?
400
H2 and O2 in this reaction; H2 + O2 ---> H2O2
What are reactants?
400
Electrons farthest away from the nucleus. Family groups (vertical) in the periodic table get their characteristic properties because of these.
What are valence electrons?
400
The number of atoms and molecules in this compound; C2H4O2 .
What is eight (atoms)?
What is one (molecule)?
400
The bonds in a water molecule, H2O.
What is a polar covalent bond?
400
One end of this molecule is polar which is attracted to water while the other end is nonpolar and is attracted to oil.
How does soap work?
500
Classify each of these reactions are decomposition, synthesis, or replacement:
a) SO3 + H2O ---> H2SO4
b) Fe + 2 HCl ---> FeCl2 + H2
What are:
a) synthesis
b) replacement
500
Draw and label a model of the atom, Beryllium. Label its protons, neutrons, and electrons.
p=4
e=4
n=5
500
(1) Draw the electron dot, or Lewis Dot, structure to show the chemical bonds in carbon dioxide, CO2. (2) Tell if it is a covalent, polar covalent, or ionic bond. (3) Label charges, if appropriate.
What is .... see the whiteboard for answer.
500
Crystal shape, high melting point, and electrical conductivity are characteristics of this type of compound.
What are three main characters of ionic compounds?