PT quiz preview

The atom with the largest atomic radius in Group 18 is - 

• Ar
• He
• Kr
• Rn

When comparing elements with the same number of occupied energy levels in their e- clouds, the greater the atomic number, the  ____ .

• weaker the attraction felt by the valence electrons

• same attraction felt by the valence electrons

• stronger the attraction felt by the valence electrons

Answer explanation

atomic number is based on # of protons.

More protons = greater nuclear charge and a greater pull on the electrons of the atom (including the outermost electrons)

A substance that is dull, brittle, and a poor conductor of electricity is a ...

• metalloid
• non-metal
• metal

Answer explanation

opposite properties of luster, malleability, and good conduction of electricity would be a Metal (elements to the left of the PT staircase line)

Unlike non-metals, most metals tend to —

• conduct electricity and heat well.
• be gases at room temperature.
• break easily when hammered.
• have less luster and shine.

Which answer correctly places 3 elements of Period 2 in increasing order of electronegativity?

• B < N < F
• B < F < N
• N < F < B
• F < N < B

Answer explanation

electronegativity increases as you examine elements of a Period from left to right.

fluorine is the furthest the right within Period 2 of the listed elements (it is, in fact, the most electronegative of ALL elements), and boron, B, is the furthest to the left of the possible elements.

Electronegativity is...

• the ability of an atom to attract electrons within a chemical bond

• the tendency of an atom to lose electrons

• the energy required to remove an electron from an atom in the gaseous state

• the size of an atom

Answer explanation

definition question.

atoms of different elements have differing abilities to attract outer electrons.

try to not confuse electronegativity with ionization energy (energy to remove an electron) or nuclear charge (simply the number of protons in the nucleus)

Ionization energy __________ as you read down a Group.

• remains the same

• changes unpredictably

• increases

• decreases

Answer explanation

ionization energy is the amount of energy to remove the most loosely held electron from an atom or ion.

As atoms become bigger and have less attraction between nucleus and outer (valence) electrons, the energy required becomes less and less.

Which has the highest ionization energy (of those listed)?

• lithium

• cesium

• sodium

• potassium

Answer explanation

All of the listed elements belong to Group 1 (the alkali metals).

As elements become bigger (lower in the Group) they have less and less hold on the valence electrons.

Therefore, higher up in the Group has higher ionization energy (Li, lithium, is highest in the Group)

Which elements have similar chemical properties?

• elements in a Group

• elements in a Period

Answer explanation

Elements in a Group have the same number of valence electrons.

valence electrons determine how an element will react.

Elements within a Period have the same number of occupied energy levels in their cloud, but that doesn't mean they'll behave similarly in chemical reactions. (They have differing amounts of electrons to lose or gain till they have the magic 8 outer electrons)

Which Group contains the most "active" nonmetals?

• Group 1, the Alkali Metals

• Group 2, the Alkaline Earth Metals

• Group 18, the Nobel Gases

• Group 17, the Halogens

• Group 16, the Chalcogens

Answer explanation

Fluorine is the most "active" nonmetal of all and it is located in Group 17, the halogens.