Atomic radius vs. atomic number

1. Which is the largest of the 54 elements?

• Rubidium (0.216 nm)

2. Describe how the atomic radius varies within a period and within a family.

• Period – atomic radius generally decreases from left to right. This is because when moving from left to right nuclear charge increases by one unit and one electron is added to the electron shell. This causes the electrons to get attracted closer to the nucleus. Or in other words, it decreases because valence electrons are being added to the same energy level at the same time as the nucleus is increasing protons.
• Family – atomic radius increases as we move downwards. This is because when moving downwards, there is an increase in principal quantum numbers which increase the number of electron shells.

3. Use the graph to predict the atomic radius of the following elements?
   1. Cesium – ~0.280 (actual: 0.267)
   2. Tungsten – ~0.135 (actual: 0.142)
   3. Thallium – ~0.165 (actual 0.171)
   4. Radon – ~0.135 (actual 0.141)
4. Which group of the main group elements contains the largest elements?

• The first group also known at the alkali metals are the largest elements. Atomic radius increases going downwards and decreases going from left to right.

Ionization Energy vs. Atomic Number

1. How would you explain ionization energy to your partner?

Ionization energy is a quantity of energy. For an electron to absorb a discharged atom of an element must be the grounded state. Ionization energy has to do with atomic radius in that the bigger the radius, the less amount of energy is needed to remove an electron from the valence shell. Ionization energy is the amount of energy needed to remove an electron. Usually, the closer the electrons are to the nucleus, the higher ionization energy it will have.

2. How does ionization energy vary within a period and a family?

• In a period when moving left to right, the ionization energy increases. This is because electrons are being held closer to the nucleus and thus the electrons are harder to remove.
• In a family when moving bottom to top, the ionization energy increases. This is because the electrons are further away from the nucleus (held in lower-energy orbitals) and so the electrons are harder to remove.
  1. Which element on your graph has the strongest hold of it’s valence electrons?
• Helium has the strongest hold of its valence electrons. This is because it has a full valence shell of electrons (2 electrons its shell). It is farthest to the right which means it has a high ionization energy, and is in the top row which also mean it has high ionization energy.

2. Write the electron configuration for chlorine.

• Cl = 1s²2s²2p⁶3s²3p⁵ à [Ne]3s²3p⁵
  1. Which electron is lost when 1251 Kj/mole of energy are applied to a sample of chlorine atoms?
• Chlorine is an atom should already be stable and thus not need to lose an electron. However, if it was an ion, chlorine would gain an electron not lose one to have a full outer shell. The new electron configuration would look like this, Cl^–= 1s²2s²2p⁶3s²3p⁶ à [Ne]3s²3p⁶

3. Compare the ionization energies of metals to non-metals.

• Non-metals have high ionization energy because there is a strong attraction between the nucleus and atoms (higher ionization to the right top). Compared with metals that are closer to the left and middle of the where most of ionization energy will be lower (low ionization energy to the left and bottom).

 

Melting Point vs Atomic Number

1. Describe the trend of melting points within a period.

• The melting point is the amount of energy required to break a bond(s) to change the solid phase of substance to a liquid. Melting points are varied and don’t generally have a distinguishable trend across the periodic table. However, certain patterns can be found from the graph. Metals generally have high melting points and most non-metals possess low melting points.

2. Which group of elements tends to have the highest melting points?

• The transition metals tend to have high melting points, specifically group 8, which consists of Fe (1535 °C) and Ru (2250 °C).

3. Tungsten is used in incandescent light bulbs because it has an extremely high melting point. Which element on your chart could a reasonable replacement for tungsten? Why?

• Carbon would be a reasonable replacement for tungsten because it has the highest melting point on the chart.

 

Density vs Atomic Number

1.

1. Describe how density varies within a period.

• From left to right on the table the density increases; however, the elements also become denser toward the center of the table and less dense towards the gaseous elements.

2. Compare the densities of the elements in the second period with the elements in the third period.

• The elements in the third period has an increase in density compared to the second period because it is further away from left side of the periodic table. For example, Li from the second period has a density of 0.53 kg/m₃, compared to Na from the third period with a density of 0.97 kg/m₃.

3. Assume that the transition metals given in the table are representative of the other members of this group. How do the densities of the transition metals compare with those of the elements in the main group?

• The transition metals generally have higher densities than the main group, their densities increase consistently compared to the elements in the main group. For example, Pd has a density of 12.02 g/cm₃, whereas the density of As is 5.72 g/cm₃.

4. Explain why aluminum and magnesium are more suitable than iron for use in some airplane parts.

• When manufacturing airplanes, some parts need to be made of light-weight materials; therefore, aluminum and magnesium are more suitable than iron because they have a lower density. Heavier metals would restrict an airplane’s ability to takeoff and fly.

Electronegativity vs. Atomic Number

1. Describe how electronegativity varies within a period.

• If going from left to right on the periodic table, the electronegativity will increase. When the valence shell of an atom is less than half full, it needs less energy to lose an electron then to gain one. However, if the valence shell is more than hall full, it’s easier to take an electron than to give one away.

2. Describe how electronegativity varies within a family.

• If going from the top to the bottom of a family, the electronegativity will decrease. Because of the atomic number increasing while going down in a family, there is more distance between the valence electrons and nucleus.

Exceptions to this: the noble gas, lanthanides, and actinides

• Noble gases already have a full valence shell and don’t attract electrons
• Lanthanides and actinides have more complicated chemistry which generally doesn’t follow a trend like the others.
• Transition metals have electronegativity values, but they don’t vary much in a family because their metallic properties affect their ability to attract electrons