Lesson Worksheet: Periodicity Chemistry

In this worksheet, we will practice describing the trends in properties across periods of the periodic table.

Q1:

The formation of ions from atoms, by the addition or loss of a single electron, affects the size of the newly formed ion compared to the original atom.

Which statement is correct when comparing the size of a cation with the corresponding atom?

  • AThe radius of the cation is smaller than the radius of the atom from which it was formed.
  • BThe radius of the cation is larger than the radius of the atom from which it was formed.
  • CThe radius of the cation is the same as the radius of the atom from which it was formed.

Which statement is correct when comparing the size of an anion with the corresponding atom?

  • AThe radius of the anion is larger than the radius of the atom from which it was formed.
  • BThe radius of the anion is smaller than the radius of the atom from which it was formed.
  • CThe radius of the anion is the same as the radius of the atom from which it was formed.

Q2:

Which of the following statements does not in part explain why the melting point of the period 3 elements increases from Na to Al?

  • AFrom Na to Al, the charge on the metal ion decreases from 3+ to 1+.
  • BThe number of delocalized electrons increases from Na to Al.
  • CThe strength of the metallic bonding increases.
  • DAll three elements are metals, so they exhibit metallic bonding.

Q3:

The table shows the values for electrical conductivity of period 3 elements.

Period 3 ElementNaMgAlSiPSClAr
Electrical Conductivity (S/m)0.2180.2240.3822×101×101×10

Which of the following statements explains why the conductivity increases from sodium to aluminum?

  • AThe ductility of the metal increases, allowing an electrical wire of greater purity to be drawn.
  • BThe number of delocalized electrons carrying the current increases due to the greater number of valence electrons.
  • CThe number of protons in the nucleus of the atom increases, attracting the free electrons more strongly.
  • DThe electrons carrying the current are freer to move as the atomic radii increase.

Which of the following statements explains the drop in conductivity from aluminum to silicon at room temperature?

  • AAluminum has a giant covalent structure and so conducts electricity better than silicon.
  • BSilicon has a greater density than aluminum and prevents a larger current from passing.
  • CSilicon does not have a metallic structure and so does not have free electrons to carry a current.
  • DSilicon has a full outer shell and so has no delocalized electrons to carry a current.
  • EAluminum has fewer delocalized electrons than silicon.

Q4:

Which of the following statements best explains why an oxygen ion (O2) has a larger ionic radius than a sodium ion (Na+)?

  • AAn oxygen ion gains electrons and forms a negatively charged ion.
  • BThere are more subatomic particles in the nucleus of an oxygen ion than in that of a sodium ion.
  • CMetal ions are always smaller than nonmetal ions.
  • DAn oxygen ion has fewer protons in its nucleus than a sodium ion.
  • EA sodium ion only has a single charge, but an oxygen ion has a double negative charge.

Q5:

A student is learning about periodicity trends of period 3 elements. She draws a sketch graph to show a trend of a property across the period but forgets to label the 𝑦-axis.

What label best fits the 𝑦-axis?

  • AMelting point
  • BAtomic radii
  • CIonic radii
  • DBoiling point
  • EElectrical conductivity

Q6:

Which of the following is correct as you move from left to right across a period in the periodic table?

  • AThe atoms get smaller due to an increase in the ionization energy.
  • BThe atoms get smaller due to an increase in the effective nuclear charge.
  • CThe atoms get smaller due to an increase in the atomic mass.
  • DThe atoms get smaller due to an increase in the electronegativity.
  • EThe atoms get smaller due to an increase in the metallic properties.

Q7:

Which of the following elements has the smallest atomic radius in the alkali metal group?

  • ARubidium
  • BCesium
  • CPotassium
  • DSodium
  • ELithium

Q8:

Why does the atomic radius of atoms get bigger as you move down a group in the periodic table?

  • ABecause the energy levels of the atoms increase
  • BBecause the ionization energy of the atoms increases
  • CBecause the number of neutrons in the atoms increases
  • DBecause the masses of the atoms increase
  • EBecause the electronegativity of the atoms increases

Q9:

Which of the following explains why the radius of the positive ion (the cation) is smaller than its atomic radius?

  • AThe atom has more electrons; therefore, the attraction force of the effective nuclear charge on the electrons increases.
  • BThe atom has more mass; therefore, the attraction force of the effective nuclear charge on the electrons increases.
  • CThe cation has more neutrons; therefore, the attraction force of the effective nuclear charge on the electrons increases.
  • DThe atom has more neutrons; therefore, the attraction force of the effective nuclear charge on the electrons increases.
  • EThe cation has less electrons; therefore, the attraction force of the effective nuclear charge on the electrons increases.

Q10:

Which of the following elements has the largest atomic radius across the periodic table?

  • ACopper
  • BCesium
  • CLithium
  • DNeon
  • EMagnesium

This lesson includes 17 additional questions and 5 additional question variations for subscribers.

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