The Periodic Table
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AP Chemistry › The Periodic Table
Which of the following elements has the largest atomic radius?
F
Na
I
Cs
Sr
Explanation
Atomic radius increases down the columns and to the left. The furthest left elements are Na and Cs. Cs is furthest down so it is the biggest.
Which of the following elements has the largest atomic radius?
F
Na
I
Cs
Sr
Explanation
Atomic radius increases down the columns and to the left. The furthest left elements are Na and Cs. Cs is furthest down so it is the biggest.
Which of the following values does not increase as you move left to right in a period of the periodic table?
Atomic radius
Electronegativity
Ionization energy
Electron affinity
Explanation
Atomic radius will decrease as you move to the right, because the atomic number of the element will be increasing. This results in a more positively charged nucleus that pulls the electrons closer to the center. As a result, atomic radius will notably decrease from left to right.
Electronegativity, ionization energy, and electron affinity all increase to the right of the periodic table.
Which of the following values does not increase as you move left to right in a period of the periodic table?
Atomic radius
Electronegativity
Ionization energy
Electron affinity
Explanation
Atomic radius will decrease as you move to the right, because the atomic number of the element will be increasing. This results in a more positively charged nucleus that pulls the electrons closer to the center. As a result, atomic radius will notably decrease from left to right.
Electronegativity, ionization energy, and electron affinity all increase to the right of the periodic table.
Which of the following atoms has the largest atomic radius?
Sulfur
Chlorine
Oxygen
Fluorine
Explanation
When predicting how atomic radius will change as you move along the periodic table, remember these two trends.
1. As you move down the table in a given group, the atomic radius of the atoms will increase.
2. As you move left to right in a given period, the atomic radius will decrease.
Knowing this, we can compare the possible options. Sulfur and chlorine are in the lowest period, so they have the largest atomic radii. Because sulfur is to the left of chlorine on the periodic table, it will have a larger atomic radius. As a result, sulfur has the largest atomic radius out of the possible options.
Which of the following atoms has the largest atomic radius?
Sulfur
Chlorine
Oxygen
Fluorine
Explanation
When predicting how atomic radius will change as you move along the periodic table, remember these two trends.
1. As you move down the table in a given group, the atomic radius of the atoms will increase.
2. As you move left to right in a given period, the atomic radius will decrease.
Knowing this, we can compare the possible options. Sulfur and chlorine are in the lowest period, so they have the largest atomic radii. Because sulfur is to the left of chlorine on the periodic table, it will have a larger atomic radius. As a result, sulfur has the largest atomic radius out of the possible options.
Refer to Figure 1 for questions 1-6.
Below are the data for ionization energies of three elements X, Y, and Z. These elements are on the third peroid of the periodic table. The first four ionization energies for elements X, Y, and Z are given below in values of kJ/mol.
Figure 1: Ionization energies in kJ/mol for selected elements.
Which of the unknown elements would you expect to share chemical properties with strontium (Sr)?
Z
X
Y
X and Y
Y and Z
Explanation
We know that element Z is magnesium due to its jump bwtween ionization energies 2 and 3. Magnesium is in the second group of the periodic table and shares similar chemical properties with other alkali earth metals, such as strontium.
Refer to Figure 1 for questions 1-6.
Below are the data for ionization energies of three elements X, Y, and Z. These elements are on the third peroid of the periodic table. The first four ionization energies for elements X, Y, and Z are given below in values of kJ/mol.
Figure 1: Ionization energies in kJ/mol for selected elements.
Which of the unknown elements would you expect to share chemical properties with strontium (Sr)?
Z
X
Y
X and Y
Y and Z
Explanation
We know that element Z is magnesium due to its jump bwtween ionization energies 2 and 3. Magnesium is in the second group of the periodic table and shares similar chemical properties with other alkali earth metals, such as strontium.
Which of the following has the highest electron affinity?
Explanation
The trend for electron affinity increases upwards through a group, and rightwards along a period. The noble gasses already have full octets, so the increasing trend stops at the halogens and the noble gasses have extremely low values. The element with the highest electron affinity is fluorine. Halogens tend to have a high values so that they can complete their almost full valence shells. Bromine has a very high electron affinity, while the bromide ion does not because it has already filled its valence octet.
Which element has the smallest atomic radius?
He
F
Cs
Na
Explanation
Helium has the smallest atomic radius. This is due to trends in the periodic table, and the effective nuclear charge that holds the valence electrons close to the nucleus. Atomic radius decreases as you move across a period from left to right and decreases as you move up a group from bottom to top. Since He is at the upper right-hand corner of the table, it must have the smallest atomic radius.