Periodic Table
If an element has an atomic number of 19 how many protons does it have?
19
Valence electrons are the same as the .....
group #
What is the difference between an atom and a molecule?
When a candle is lit, the wick burns, the wax melts, the candle changes shape, and the air around the candle heats up. Which of the following is an example of a chemical change?
wick burning
Two elements in the same group share....
# of VE and similar characteristics
Fluorine is in group 7 on the periodic table...how many valence electrons does it have?
7
Is sodium an element or a compound?
element
When sodium hydroxide is added to water the temperature goes from 20 C to 29 C. What is this an indication of?
exothermic reaction
How do you determine the number of neutrons in an element?
Atomic Mass- Atomic Number
How many VE are in the element Ne?
Table salt is sodium chloride. If you were able to take table salt and separate it into sodium and chlorine, what would the smallest unit of each component be?
an atom of sodium and an atom of chlorine
When solid S1 is heated, it breaks up into gas G and another solid S2. The solids S1 and S2 and the gas G are all pure substances. Based on this information alone, which substance or substances must be compounds?
S1
JJ Thompson’s theory thought that atoms were composed purely of negatively charged electrons. This model became known as the plum pudding model. How does this model compare to what we know about atoms today?
electrons are in shells around the nucleus and protons and neutrons are in the nucleus
How many VE electrons are in the element MG? What does that element want to do?
2 either gain 6 or get rid of 2
The plastic I had reflected a lot of light and would not bend...these are observations of what?
physical properties of luster and flexibility (malleability)
Sabrina was asked by a classmate why she would place hydrogen in the first column of the periodic table. Which of the following reasons could she give as a response?
I. Hydrogen combines with chlorine in the same atomic ratio as sodium.
II. Hydrogen is a gas at room temperature.
III. Hydrogen forms diatomic molecules.
A. I and II
B. II and III
C. I only
D. III only
C
Helium (He) is an unreactive gas with an atomic number of 2 and an atomic mass of 4. Krypton (Kr) is found three rows below Helium (He) in the same column of the periodic table. Why is Krypton grouped below Helium in the periodic table?
it is also an unreactive gas
Why are the elements in group 8 unreactive while the elements in group 1 are highly reactive?
8 has full outer shell
Why would it be best to use data from all groups to make a single graph?
Ensure validity of results
When sodium hydroxide and silver nitrate are combined in a test tube, bubbling occurs causing the temperature of the test tube to become warm. After a period of time, a new solid substance appeared in the test tube. What describes the result?
a chemical change with precipitate formation