Balancing Equations
What does it mean to balance a chemical equation?
A. To make sure both sides have the same number of each type of atom
B. To make the equation look neat
C. To make sure there are more products than reactants
D. To increase the number of molecules
Which statement BEST describes the structure of an atom?
A. Atoms are solid and indivisible.
B. Atoms are mostly empty space with a dense nucleus.
C. Atoms are flat and contain no space.
D. Atoms have only electrons and no protons.
The modern Periodic Table organizes elements by
A. Atomic mass
B. Atomic number (number of protons)
C. Density
D. Number of neutrons
Metals are generally —
A. Dull and poor conductors
B. Brittle and nonreactive
C. Shiny, malleable, and good conductors
D. Liquids at room temperature
What are the three common states of matter?
Solids , Liquid , Gas
Which law explains why equations must be balanced?
A. Law of Energy Transfer
B. Law of Conservation of Mass
C. Law of Thermodynamics
D. Law of Chemical Reactions
Where are protons and neutrons located in an atom?
A. In the electron cloud
B. In the nucleus
C. Outside the atom
D. In the outermost shell
Who is credited with creating the first periodic table?
A. John Dalton
B. Ernest Rutherford
C. Dmitri Mendeleev
D. Marie Curie
Nonmetals are typically —
A. Good conductors
B. Brittle and poor conductors
C. Dense and shiny
D. Magnetic
Which statement best describes all matter?
A. All matter is made up of one element.
B. All matter has mass and takes up space.
C. All matter is a gas.
D. All matter is made of energy.
Which equation is balanced?
A. H₂ + O₂ → H₂O
B. 2H₂ + O₂ → 2H₂O
C. H₂ + 2O₂ → H₂O₂
D. 2H + O₂ → H₂O
Where are electrons found in an atom?
A. In the nucleus
B. On the outside surrounding the nucleus
C. Mixed with neutrons
D. Inside protons
Mendeleev arranged his table according to atomic mass and noticed —
A. Patterns in chemical properties repeated in regular intervals
B. The elements had no relationship
C. Metals were heavier than nonmetals
D. Atoms were solid and indivisible
The most unreactive elements on the periodic table are
A. Alkali metals
B. Halogens
C. Noble gases
D. Transition metals
What is the smallest unit of matter that still has the properties of an element?
A. Atom
B. Compound
C. Mixture
D. Molecule
In the equation below, what number should go in front of Fe to balance it?
___ Fe + O₂ → Fe₂O₃
A. 1
B. 2
C. 3
D. 4
Which particle has a positive charge?
Proton
The modern periodic table is arranged by —
A. Increasing atomic mass
B. Increasing atomic number
C. Alphabetical order
D. Reactivity only
Metals are usually located on the
A. Left side and center
B. Right Side
C. At the bottom
Which of the following is an example of a physical change?
A. Iron rusting
B. Ice melting
C. Wood burning
D. Baking a cake
What do the numbers placed in front of chemical symbols represent?
A. Subscripts
B. Coefficients
C. Electrons
D. Exponents
Which particle has a negative charge
Elements in the same group or column have similar —
A. Colors
B. Physical sizes
C. Chemical properties and reactivity
D. Atomic masses
True or False? Periods are located horizontally in the periodic table
True
Ice Cream melting is a physical or chemical change?
Physical