Unit 3 Mid-Unit Practice Test

Which of the following is the electron configuration to an electrically neutral halogen? A. 1s2 2s1 B. 1s2 2s2 2p6 3s2 C. 1s2 2s2 2p6 D. 1s2 2s2 2p5

D. 1s2 2s2 2p5 You can tell it's a halogen because it has seven electrons in level 2 (the last of it's levels; 2s and 2p are sub-shells within level 2). All halogens have seven electrons in their last level (aka seven valence electrons).

Which of the following electron configurations is that of a halogen? A. 1s22s22p6 B. 1s22s22p63s1 C. 1s22s22p63s2 D. 1s22s22p5

D. 1s22s22p5 A halogen is any element that is in group 7A and has an electron configuration that ends in p.

How many valence electrons are in the outermost shell of all the halogens? A. 1 B. 8 C. 2 D. 7

D. 7 The halogens are in group 7A and have 7 valence electrons.

When creating the periodic table, how did Dmitri Mendeleev account for elements that had not been discovered yet? A. He created the elements that were missing in the laboratory B. He gave them placeholder names and put them on his periodic table C. He ignored them and worked with what he had D. He left blank spaces on the table so that when the element was discovered, he could just add it in

D. He left blank spaces on the table so that when the element was discovered, he could just add it in

Which series of atomic numbers represents the ordering of consecutive elements within the periodic table? A. 5, 6, 7, 8 ... B. There cannot be any consecutive elements within the periodic table C. 9, 18, 27, 36 D. 50, 60, 70, 80

A. 5, 6, 7, 8 ... 5, 6, 7, and 8 are 'consecutive' because they are in an order such as 1,2,3; each comes directly after the one before it without skipping any.

Which element has four energy levels (electron shells)? A. Bromine (Br) B. Carbon (C) C. Oxygen (O) D. Sulfur (S)

A. Bromine (Br) Bromine is in period (row) 4 on the periodic table. This means it has 4 energy levels.

Which of the following has the largest atomic radius: Mg2+, Mg, Ca2+, or Ca? A. Ca B. Ca2+ C. Mg2+ D. Mg

A. Ca The atomic radius increases as you get closer to the bottom left corner. Ca is an atom, so it has an atomic radius.

Use a periodic table to help you determine which atom has a larger atomic radius (size). A. Carbon (C) B. Fluorine (F) C. Oxygen (O) D. Nitrogen (N)

A. Carbon The closer to the bottom left corner, the bigger the atom is; hence the bigger the atomic radius is.

How does the current (modern) periodic table differ from Mendeleev's periodic table? A. It is now arranged by increasing atomic number instead of increasing atomic mass. B. The atomic masses on the modern periodic table are much different than they were on Mendeleev's periodic table. C. It contains more elements than Mendeleev's periodic table. D. Mendeleev's periodic table didn't group the elements, but were just a long list.

A. It is now arranged by increasing atomic number instead of increasing atomic mass. *AND* C. It contains more elements than Mendeleev's periodic table.

Which word best matches this definition? "When elements are arranged in order of increasing atomic number, there is a recurring pattern to their chemical and physical properties" A. Periodic Law B. Law of the Periodic Table C. Elemental Law D. Law of Chemical and Physical Properties

A. Periodic Law

Which of the following element has similar chemical and physical properties to carbon (C)? A. Si B. N C. B D. Al

A. Si Elements in the same family (aka group, aka column) have similar properties.

Which element has the same number of main energy levels as Argon (Ar) and the same number of valence electrons as oxygen (O)? A. Sulfur (S) B. Iron (Fe) C. Arsenic (As) D. Silicon (Si)

A. Sulfur (S) Same main energy level = Same period/row Same number of valence electrons = Same family/column

Chromium (Cr) has the most properties in common with [...]. A. Tungsten (W) B. Zirconium (Zr) C. Silver (Ag) D. Manganese (Mn)

A. Tungsten (W) Elements within the same family/column have similar properties.

Elements in a period on the periodic table [...]. A. have different properties that repeat across the next period. B. have different properties that show no pattern. C. have similar symbols. D. have the same number of valence electrons.

A. have different properties that repeat across the next period. The periods are the rows of the periodic table.

Barium is a radioactive metal that is used for medical purposes. Which group does Barium (Ba) belong to? A. Heavy Metals B. Alkaline Earth Metals C. Alkali Metals D. Transition Metals

B. Alkaline Earth Metals

Which atom would have the largest radius? Hint: Be careful to consider how charge affects the size of the atom. A. Ca2+ B. Ca C. O2- D. O

B. Ca Calcium is larger for two reasons: a.) it's below oxygen on the periodic table meaning it has more electron shells b.) its positive ion (Ca2+) has fewer electrons in the cloud, making it smaller than the neutral calcium atom.

Which element has 3 electron shells (energy levels)? A. Fluorine (F) B. Chlorine (Cl) C. Boron (B) D. Scandium (Sc)

B. Chlorine (Cl) Chlorine is the only element here in period (row) 3 of the periodic table.

Which of the following places the elements in the correct order of increasing first ionization energy? A. Be, Mg, Ca B. P, S, Cl C. Cl, S, P D. Rb, Cs, Fr

B. P, S, Cl Ionization energy increases as you get closer to the upper right corner.

What do the periods (rows) and groups (columns) on the periodic table tell us? A. Periods tell us how many valence electrons and groups tell us if the chemical reactions are similar. B. Periods tell us the number of electron shells and groups tell us the number of valence electrons. C. Periods tell us how many orbitals are in the electron, and groups tell us the entire number of electrons in the atom. D. Periods are equal to the number of valence shells and groups tell us the size of the atoms.

B. Periods tell us the number of electron shells and groups tell us the number of valence electrons.

Which of the following has the smallest first ionization energy: F, Be, Sr or Ra? A. F B. Ra C. Be D. Sr

B. Ra Ionization energy is highest near the upper right corner, but lowest near the bottom left corner.

How many valence electrons are in the outermost shell of all alkaline earth metals? A. 1 B. 8 C. 2 D. 0

C. 2 Alkaline Earth Metals are in Family (aka group or column) 2 (the second column), so that means they have 2 valence electrons.

Oxygen needs [...] more electron(s) to fill its outer shell. A. 3 B. 1 C. 2 D. 4

C. 2 Oxygen is two away from the closest noble gas (Ne). If it just gains two electrons, it will have a full octet (full outer shell) just like Ne. And that's sort of the goal for all elements; to have the same number of electrons as the closest noble gas. That full outer shell is very stable.

Which element has the same number of valence electrons as helium (He)? Hint: Be careful about which number of valence electrons helium has. While it is in group 8A, it is the one exception to this group A. Hydrogen (H) B. Neon (Ne) C. Beryllium (Be)

C. Beryllium Beryllium has 2 valence electrons because it's in group (column) 2A.

Which element has the same number of valence electrons as Lithium (Li)? A. Neon (Ne) B. Sulfur (S) C. Francium (Fr) D. Barium (Ba)

C. Francium Elements within the same family (column) have the same number of valence electrons... that's what gives them similar properties.

Which statement is NOT true about the first ionization energy of an atom or ion? A. It is the amount energy required to remove an electron from an atom or ion B. It depends on the nuclear charge of the atom or ion C. It increases as atomic size increases D. It depends on the electron distance from the nucleus of the atom or ion

C. It increases as atomic size increases Atomic size increases as you get closer to the bottom left corner, but ionization energy is the opposite; it increases as you near the upper right corner.

Which of the following groups of elements has been arranged by increasing ionization energy? (smallest IE to biggest IE) A. C --> Na --> K B. C --> K --> Na C. K --> Na --> C D. K --> C --> Na

C. K --> Na --> C Ionization energy increases as you go up and to the right on the periodic table.

Which of the following elements has the greatest first ionization energy? A. Fe B. C C. O D. H

C. O

The first periodic table that was arranged by Dmitri Mendeleev was arranged by... A. The atomic number / number of protons B. The atomic radius / size C. The atomic mass of each element D. The element's physical properties such as density and melting point

C. The atomic mass of each element Mendeleev arranged the periodic table in order of increasing atomic mass. When he did this, he noticed that chemical patterns began to repeat themselves.

What happens to the size of the radius of the atom when it becomes positively charged? Hint: Think about how any atom can become positively charged - does it mean it gained or lost negative electrons? A. the atomic radius decreases because the atom gained electrons B. The atomic radius increases because the atom gained electrons C. The atomic radius decreases because the atom lost electrons D. The atomic radius increases because the atom lost electrons

C. The atomic radius decreases because the atom lost electrons Losing negative electrons results in a positive charge and a smaller radius

What happens to the size of an atom as you move from left to right along a period on the periodic table? A. The size decreases because there are fewer electron shells. B. The size increases because more electron shells are added. C. The size decreases because more protons pull the valence electron shell closer to the nucleus. D. The size increases because more protons are being added.

C. The size decreases because more protons pull the valence electron shell closer to the nucleus. As the atomic number increases from left to right, so does the number of protons. These protons attract the negative electron shells closer to the nucleus, thereby decreasing the size of the atom.

Atomic size of the elements increases [...]. A. as one moves from left to right in a period B. as one goes from the bottom to the top of a group C. as one moves from top to bottom in a group D. randomly across a period or down a group

C. as one moves from top to bottom in a group Remember that atoms get bigger as you get closer to the bottom left corner of the periodic table. So they get bigger as you go from top to bottom or from right to left.

When elements are arranged in order of increasing atomic number, [...]. A. elements with higher atomic numbers within a period are heavier than elements with lower atomic numbers B. there is a recurring pattern only to their physical properties C. there is a recurring pattern to their physical and chemical properties D. elements are alphabetized

C. there is a recurring pattern to their physical and chemical properties This is called the Periodic Law

For the A groups (Groups 1A to 8A), the group number is equal A. to the number of core electrons B. to the total number of electrons in the element C. to the number of valence electrons D. to the block number of the sublevel

C. to the number of valence electrons For these groups (columns), the number equals the number of valence electrons.

Which of the following elements have properties similar to those of Xenon (Xe)? A. F, Br, I B. Na, Mg, Al C. Ti, V, Cr D. Kr, Ar, Ne

D. Kr, Ar, Ne Elements within the same family (column) have similar properties.

What scientist arranged the periodic table by increasing mass number? A. Madame Curie B. Moseley C. Mickey Mouse D. Mendeleev

D. Mendeleev Dmitri Mendeleev created the first periodic table of the elements.

Which element has the same energy level as Magnesium (Mg) and the same number of valence electrons as Nitrogen (N)? A. Arsenic (As) B. Carbon (C) C. Calcium (Ca) D. Phosphorous (P)

D. Phosphorous (P) Phosphorous is in the same period (row) as Magnesium so it has the same energy level. It is also in the same group (column) as Nitrogen, so it has the same number of valence electrons.

What statement is true of noble gases? A. They are the most reactive group of the periodic table B. They have one valence electron C. They have 7 valence electrons D. They have 8 valence electrons

D. They have 8 valence electrons Most noble gases have 8 valence electrons, which is very stable. That's why they don't react. Helium, however, only has two valence electrons because it only has two electrons total.

Why are noble gases unreactive? A. Because they are gases B. They have 2 valence electrons C. The outermost shell is almost full D. They have a full valence shell

D. They have a full valence shell All noble gases have the maximum number of valence electrons in their outermost shell. This means they do not seek to gain or lose any electrons and are unreactive.

Calcium (Ca) has [...] main energy levels. A. six B. two C. seven D. four

D. four Calcium is in period/row 4, so it has four main energy levels.

Iodine needs one more electron to fill its outer shell. What is the name of the group to which iodine belongs? A. alkaline earth metal B. alkali metal C. noble gas D. halogen

D. halogen Iodine is in the second-to-last group (aka family, aka column) on the right. We call these the halogens.