Unit 0
How many significant figures are in the number 0.0030450
5
What is the mass number of an atom that contains 21 electrons, 21 protons, and 24 neutrons?
45
What group number are the halogens found in?
17
Find the element on the Periodic Table, look for the last number on the electron configuration, the last number is how many dots are drawn around the symbol of the element.
Which of the following cannot be decomposed into simpler substances?
1) elements 2) solutions 3) mixtures 4) compounds
1) elements
Calculate the following to the correct number of significant figures:
56.78 + 3.4 + 3252.54 = __________
3312.7
What is the maximum number of electrons that can be contained in the n=4 principal energy level?
32
(2+6+10+14)
Elements with similar chemical characteristics are found in the:
1) same group 2) same period
1) same group
What temperature is absolute zero?
0 Kelvin (K)
What is the general trend for first ionization energy and electronegativity demonstrated by Group 15 elements going from the top to bottom?
They both decrease
Calculate the following to the correct number of significant figures:
54 x 3.89 x 2.6 = __________
550
Describe how you can identify if an electron configuration is in an excited state?
You would see that an electron jumped up to a higher shell, and a lower shell is missing an electron.
Atomic radius increases as you go which two directions on the periodic table? (up, down, left, right)
Left, Down
What is the maximum number of electrons that can occupy an orbital?
2
What is the term that refers to how strongly an atom of an element attracts electrons in a chemical bond with atom of different element?
Electronegativity
Burning is an example of what type of change?
Chemical
What were the 2 conclusions made from the Gold Foil Experiment? (You must name both)
1) the atom is made of mostly empty space
2) there is a small, dense, positive nucleus
What is the definition of ionization energy (aka first ionization energy)?
The minimum energy required to remove an electron.
What kind of elements would form a colored solution?
Transition metals or transition elements
At STP, which physical property of aluminum always remains the same from sample to sample?
1) volume 2) mass 3) density 4) length
3) density
A 7.00 g sample of water is heated and the temperature rises from 10.0 degrees Celsius to 15.0 degrees Celsius, what is the total amount of heat energy absorbed by the water? (With correct significant figures)
146 J
Find the average mass of a sample of magnesium that contains 70.4% Mg-24, 12.0% Mg-25, and 17.6% Mg-26. Answer to the nearest hundredth.
24.47 amu
As an atom gains electrons, what happens to it's atomic radius?
It increases
Does a metallic element tend to gain or lose electrons? And is a positive or negative ion formed?
Lose electrons = positive ion
Which one of the following statements explains why neon is a Group 18 element?
1) it has a low melting point
2) it has 2 electrons in the first shell
3) it is a gas at STP
4) it's atoms have a stable valence electron configuration
4) it's atoms have a stable valence electron configuration