Periodic Trends Quiz

What is the atomic radius of an atom defined as?

• The distance between the nucleus of an atom and its outermost electron

• The total distance across an atom

• One-half the distance between the nuclei of two atoms in a crystal lattice

• One-half the distance between the nuclei of identical atoms that are bonded together

Why is the size of atoms important?

• It determines the atomic mass of elements.

• It helps explain the behavior of atoms or compounds.

• It defines the number of protons in an atom.

• It is used to determine the color of the atom.

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How is the atomic radius measured to standardize the measurement of atomic radii?

• By measuring the radius of the atom's orbitals

• By measuring the distance between the nuclei of two different atoms

• By measuring one-half the distance between the nuclei of identical atoms that are bonded together

• By measuring the distance from the nucleus to the edge of the electron cloud

What is the atomic radius of a hydrogen atom based on the inter-nuclear distance between two hydrogen atoms in an H2 molecule?

• 37 pm

• 74 pm

• 148 pm

• 0.74 pm

How does the atomic radius generally change as you move from left to right across a period in the periodic table?

• It generally increases.

• It generally decreases.

• It remains constant.

• It fluctuates unpredictably.

What is the general trend in atomic radius as you move down a group in the periodic table?

• It generally decreases.

• It generally increases.

• It remains constant.

• It fluctuates unpredictably.

Why does the atomic radius decrease across a period?

• Because electrons are added to the same principal energy level and the increased positive charge pulls electrons closer to the nucleus.

• Because the number of protons decreases, reducing the nuclear charge.

• Because the electron-electron repulsions increase significantly.

• Because the principal energy levels are removed, making the atom smaller.

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Why does the atomic radius increase down a group?

• Because the number of occupied principal energy levels increases, outweighing the increase in nuclear charge.

• Because the nuclear charge decreases, reducing the pull on the electrons.

• Because the atoms lose electrons and become positively charged.

• Because the electron-electron repulsions decrease down a group.

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What happens to the atomic radius as the atomic number increases within a period?

• The atomic radius increases.

• The atomic radius decreases.

• The atomic radius remains constant.

• The atomic radius fluctuates unpredictably.

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What is ionization energy?

• The energy required to add an electron to an atom.

• The energy required to remove a proton from an atom.

• The energy required to remove an electron from an atom.

• The energy required to break a chemical bond.

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