The video tutorial explores the concepts of atomic and ionic radii. It begins with an introduction to atomic radius, explaining how it is measured and the challenges due to the electron cloud. The tutorial then discusses trends in atomic radius within groups and periods of the periodic table, highlighting the effects of electron shielding and nuclear charge. The video also covers ionic radius, explaining how cations and anions form and how their sizes compare to neutral atoms.

Why is it difficult to define a fixed atomic radius for an atom?

• Because the nucleus is too small to measure.

• Because atoms can change size depending on temperature.

• Because the electron cloud does not have a clear boundary.

• Because atoms are always in motion.

How do chemists approximate the atomic radius of an atom?

• By using the atomic number.

• By calculating the volume of the atom.

• By measuring the distance between the nuclei of two bonded atoms and halving it.

• By measuring the diameter of the electron cloud.

What happens to the atomic radius as you move down a group in the periodic table?

• It decreases.

• It fluctuates randomly.

• It remains the same.

• It increases.

Why does the atomic radius increase as you move down a group?

• Because the number of protons decreases.

• Because the atoms lose electrons.

• Because the nucleus becomes less dense.

• Because electrons are added to higher energy levels farther from the nucleus.

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What happens to the atomic radius as you move across a period from left to right?

• It increases.

• It fluctuates randomly.

• It remains the same.

• It decreases.

Why does the atomic radius decrease as you move across a period?

• Because the number of protons decreases.

• Because the number of inner shell electrons increases.

• Because the increased positive charge pulls outer electrons closer.

• Because the atoms lose electrons.

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What is a cation?

• An atom with more neutrons than protons.

• An atom that has gained an electron.

• An atom that has lost an electron.

• An atom with a neutral charge.

How does the size of a cation compare to its neutral atom?

• It is smaller.

• It is larger.

• It fluctuates randomly.

• It is the same size.

What happens to the size of an atom when it gains an electron to form an anion?

• It remains the same size.

• It fluctuates randomly.

• It becomes larger.

• It becomes smaller.

Why is the anion larger than the neutral atom?

• Because the added electron increases repulsion among electrons.

• Because the nucleus expands.

• Because the atom loses energy.

• Because the number of protons increases.