Chemistry Sem A Sem 1
Alkali metals tend to form ions with what charge?
+1
Halogens tend to form ions with what charge?
-1
What is the correct standard notation for 4.5 x 10-4?
0.00045
How many significant figures are in the following number: 0.0105
0.0105 3 significant figures
What is 0.80136 expressed with four significant figures?
0.8014
An elemental metal contains how many types of atoms?
1
How many calcium atoms are in the correct formula for calcium chloride?
1
How many fluorine atoms are in the correct formula for hydrofluoric acid?
1
Groups ________ and _______contain elements whose valence electrons are only found in the s block?
1, 2
What charge does a beryllium ion exhibit?
2+
Nitrogen can be found in Period ________ and Group ________?
2, 15
How many calcium atoms are in the correct formula for calcium phosphide?
3
How many bonded pairs of electrons are there in the molecule HCCH?
5
What are the most reactive metals on the periodic table?
Alkali metals
____________ have low ionization energies because ____________.
Alkali metals; they have the weakest effective nuclear charge in a period.
Mendeleev organized elements in the Periodic Table by _______________________ while Mosley used _________________________
Atomic mass, atomic number
Sodium Bicarbonate is often referred to as baking soda. It has a chemical formula of NaHCO3. Which of the following statements correctly describes why baking soda is considered to be a compound?
Baking soda can be broken down into other substances by chemical means
Why are noble gases unreactive?
Because they have a full valence shell of electrons.
Which is not a property of metals?
Brittle
What element is in Period 4 Group 17?
Bromine
How are elements in a period on the modern Periodic Table arranged?
By increasing number of protons
Which of the following would be a plausible next move if a scientist's repeated experiments did not support his hypothesis?
Change the hypothesis and conduct a new experiment
A property of matter must change the identity of the molecules in the substance in order to observe the property. We would classify this as a ________ property of matter?
Chemical
A specific property can only be tested by changing the molecular composition of a sample. What type of change is this?
Chemical
What type of change is photosynthesis?
Chemical
____________ changes involve changing the molecules of a sample to test chemical properties.
Chemical
What is the name of the following compound: Cr(NO3)3?
Chromium(III) nitrate
Which of the following is an example of a physical change?
Cutting a piece of paper in half using scissors
The following observations were all made of an unknown substance in a laboratory. Which of these is a physical property?
Density of the substance is 1.75 g/mL
Knowing the relationship between energy and frequency and the equation that relates the two, what is the relationship between x and y in the following equation? x = (28)y
Direct
Which of the following is was not a conclusion from Rutherford's experiments with gold foil?
Electrons are outside the nucleus at very specific energy levels.
Mass is what type of property?
Extensive
Mass of a substance is a (n) __________ property.
Extensive
Volume is what type of property?
Extensive
True or False: All metals have high melting points.
False
True or False: Most metals are found to occur naturally in their uncombined states.
False
Which of the following properties can be listed as a physical property?
Freezing point of water is 32° F
Nonmetals tend to _________ electrons and form _______ ions.
Gain, negative
Which of the following elements would have three valence electrons?
Gallium, Ga
The following observations were taken regarding a sample of matter. What is the state of matter for this sample? Sample's volume changes from 10.4 L, to 0.59 L Shape of sample of matter depends on the container it is in.
Gas
The state of matter that has an indefinite volume, and is compressible is;
Gas
Which of the following states of matter, are correctly paired with its characteristics?
Gas: Compressible, indefinite volume, indefinite shape
Which tool would be used to most accurately measure the volume for a liquid?
Graduated cylinder
In any given period, which family will experience the strongest effective nuclear charge and why?
Halogens because they have the most number of protons.
Which of these hypothesis would be most easily tested?
If acetic acid is added to a mold colony, the colony will be reduced in size.
If the volume of a substance could be changed, and the molecules could be squished together, we would label this as;
Indefinite, compressible
Boiling Point is what type of property?
Intensive
Density is what type of property?
Intensive
Freezing point is what type of property?
Intensive
Density of a substance is an ________ property, because _________.
Intensive property; density does not change when more substance is added
The state of matter that is incompressible with an indefinite shape is;
Liquid
Metals tend to ________ electrons to form a ________ ion.
Lose, positive
An isotope with 7 protons and 8 neutrons would have which of the following isotope notations?
N - 15
Argon is a gas at room temperature and has a very stable electron configuration. Which of the following elements would you expect to be gaseous and stable at room temperature?
Neon
Why can a scientific hypothesis never be completely proven true?
New evidence might become available that contradicts a scientific hypothesis.
Which of the following atoms will form an ion with a radius larger than that of its neutral atom?
O
Which of the following statements would be the hypothesis most easily tested?
Oak trees grow tallest between temperatures of 10 and 40 degrees Celcius.
A sample of hydrogen gas has a volume of 18.3 mL. This volume decreases to 15.3 mL when the temperature of that gas decreases. This type of change can be labelled as _______.
Physical
If a property of matter must go through a physical change in order to test it, we would call that a _____________ property.
Physical
The air inside of a hot air balloon is heated. The balloon slowly expands until the entire balloon lifts off the ground. What type of change is this?
Physical
What type of change is boiling water?
Physical
What is the name of the following compound: K3N?
Potassium nitride
Name the alkaline earth metal in period 7.
Radium
Which atom is most likely to attract electrons in a bond?
S
Which of the following does not represent a limitation of science?
Science cannot test observations about the natural world.
A sample of matter is both incompressible, and has a definite shape. This sample could be which of the following states of matter.
Solid
What state of matter is incompressible, and has a definite shape?
Solid
The compressibility of solids is;
The compressibility of solids is;
What family contains the most chemically active non-metals?
The halogens
The compressibility of liquids are;
The same as solids, and less than gases
Which of the following is NOT shown in an electron configuration?
The spin of the electrons.
What is the most important factor in determining a trend from left to right across a period?
The strength of the nuclear charge
How are electrons arranged in metallic bonds?
They are delocalized and free-floating.
Even though elements like Na, Li, K, and Ca, Mg, Ba share some similarities, why are they grouped into different families on the Periodic Table?
They have different chemical properties
Why do elements in the same group share the same chemical properties?
They have the same number of valence electrons.
Why do metals bend and not break?
They share electrons in discrete bonds.
True or False: Metals are good conductors of heat and electricity.
True
What do all members of a group have in common?
Valence electrons
When would an established scientific theory most likely be revised or replaced?
When new information is gathered that does not support the current theory.
Which of the following statements is the best definition of a scientific hypothesis?
a proposal that can be tested in an experiment
Which best defines a scientific theory?
a well-established, highly-reliable explanation of a natural event.
The properties of elements reoccur periodically, demonstrating periodic trends when the elements are arranged in order of increasing
atomic number
The amount of energy that an electron has normally is best referred to as its ______.
ground state
When handling hot containers, you must use caution because:
hot glass and cold glass look the same
Long hair should be tied back when working in a lab because
it could catch on fire
Which of the following can science be used to investigate?
nature
Which of the following is NOT a good lab practice?
once heated, leave chemicals to go to the restroom
Pick the answer choices that best complete the following sentence A ____________ change is observed when a substance is modified, but the molecular composition remains consistent. This type of change helps identify _________ properties of that substance.
physical, physical
All equipment for an experiment should be:
placed as far away from the edge as conveniently possible
All of the following are good lab techniques EXCEPT:
pour all chemicals down the drain
4. When heating chemicals, remember to do all of the following EXCEPT:
seal the container
What is the most important factor in determining a trend from top to bottom in a group?
the distance between the valence electrons and the nucleus
Suppose you were to read about a scientific statement based on data from hundreds of years of research and observation that applies to a broad set of naturally occurring events. Would you consider it a hypothesis or a theory?
theory
The proper method for making an acid solution is
to slowly add acid to water
