CHEM MIDTERM REVIEW Tussey
the bond angle for any tetrahedral molecule is
109.5
How many electrons can each orbital hold?
2 electrons
what is the maximum number of electrons in the first, second and third energy levels
2,8,18
how many cm are in 25 Kilometers
2.5 X 10 to the sixth
What is the volume of 25.0 g of copper if the density of copper is 8.9 g/cm3?
2.8 cm
Which of these measurements is expressed to three significant figures?
0.007
What is the density of an object having a mass of 8 g and a volume of 25 mL?
0.32 g/mL
one difference between a mixture and a compound is that
A compound can be separated into its components by chemical means
the representative elements are
Group A elements
alkenes
Hydrocarbons with one or more carbon-carbon double bonds
alkynes
a carbon compound with a carbon-carbon triple bond.
a transmutation reaction much always involve
a change in the number of protons in a nucleus of the atom
the lowest whole-number rain of ions ins an ionic compound is called
a formula unit
alkane
a hydrocarbon containing only single covalent bonds
a conversion factor
a ratio of equivalent measurements
The closeness of a measurement to its true value is a measure of it's
accuracy
which of the following can't be classified as a substance?
air
a mixture of two or more elements, at least one of which is a metal
alloy
ionizing radiation that consists of helium nuclei is
alpha
Ester
an organic compound made by chemically combining an alcohol and an organic acid
The sum of protons and neutrons in an atom equals the
atomic number
the modern periodic table is arranged in order of increasing
atomic number
dalton theorized that atoms are indivisible, but the discovery of ___ particles changed this theory
atoms of an element can have different number of protons
why did JJ Thomson believe that electrons must be a part of the atom
cathode rays are attracted to pos. magnetic plates
an atomic species with 33p+, 39n*, and 36e- is an
cation
statement concerning ions
cations form when an atom loses electrons
An -ite or -ate ending on the name of a compound indicates that the compound:
contains a polyatomic anion
Which of the following is an example of a chemical change?
cooking meat
which 2 elements steal electrons to fill an inner shell
copper and chromium
As the number of electrons added to the same principal energy level increases, atomic size generally
decreases
atomic sizes generally
decreases from left to right across a period
Light is emitted when an electron
drops from a higher to a lower energy level
An ionic compound
electrically neutral, held together by ionic bonds, composed of anions and cations
transuranium elements
elements with atomic numbers greater than 92
An unstable nucleus
emits energy when it decays
When selenium atoms form ions, they
gain 2 electrons
the most penetrating form of radiation is
gamma radiation
Electronegativity
generally decreases as you move down a group
metals are typically
good conductors of electricity, ductile, and malleable
The relative atomic mass of an atom can be found by
grams
homogeneous mixtures
have a uniform composition
all types of matter
have mass and take up space
Diatomic molecules are
hydrogen, nitrogen, oxygen, fluorine, chlorine, bromine, iodine
the correct name for Fe^2+ is
iron (II) ion
what is true about alpha particles
it has a mass of 4 amu, a helium nucleus, and contains two neutrons
what describes a solid
its particles are packed tightly together
Which of the following has the metric prefixes in order from largest to smallest?
kilo, deca, deci, nano
a three atom molecules can be
linear
a metric unit of volume is the
liter (L)
Which element, when combined with chlorine, would most likely form an ionic compound?
lithium
the melting and boiling points of most molecular compounds are
lower than those of most ionic compounds
Examples of physical change
melting, freezing, vaporization, condensation, sublimation
what ion is larger than the neutral atoms
negative ions
All atoms of the same element have the same
number of protons
the first three electrons that enter into p orbitals must have
opposite spins
horizontal and vertical columns in the periodic table
period, group
the elements in any group of the periodic table have similar
physical and chemical properties
If a bonding pair of electrons is unequally shared between two atoms, the bond is
polar covalent
a cation is any atom or group of atoms with
positive charge
the nucleus of an atom is
positively charged and has a high density
transition metals with more than one ionic charge
roman numeral
isotopes of the same element have
same number of protons but different number of neutrons
Which of the following is a heterogeneous mixture?
soil, oil and vinegar
characteristics of ionic compounds
solid at room temp, soluble in polar solvents, electrical conductivity in solution, low thermal conductivity
another name for a homogeneous mixture is
solution
If an isotope undergoes beta emission
the atomic number changes
alkaline earth metals
the elements in Group 2A of the periodic table
which statement is true of any chemical reaction
the mass of the reactants equals the mass of the products
The identity of an element can be determined on the basis of which of the following?
the number of protons in an atom of the element
the electron configuration of the F- is
the same as the neon atom
Atoms are electrically neutral because
they contain equal numbers of protons and electrons
According to the rules of significant figures, the number of digits that are estimates in measurement is
two
a metallic bond is a bond between
valence electrons and positively charged metal ions
Which of the following is a compound?
water
a covalent bond forms
when atoms share electrons
The temperature reading of -14⁰C corresponds to a Kelvin reading of
259 K
When an aluminum atom loses its valence electrons, what is the charge on the resulting ion?
3+
Express the product of 4.0 x 10-2m and 8.1 x 102 m using the correct number of significant digits.
3.2 x 10 m
A student measures a volume as 250 mL, whereas the correct volume is 240 mL. What is the percent error?
4.2 %
An atom of an element with atomic number 48 and mass number 120 contains
48 p and e & 72 n
what is the result of converting 48 m to centimeters
4800 cm
How many sig figs are in 2103.2?
5
how many valence electrons does an atom of halogen have
7
scientific notation for 0.000 008 62
8.62 x 10^-6
which of the following elements is a metalloid
As
Ether
C-O-C
How does an ionic bond form?
Particles that have opposite charges are attracted to each other.