Atomic Radii and Ionization Energy Trends

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Questions and Answers

What is the primary reason for the large decrease in first ionisation energy between elements R and S?

R has a smaller atomic number than S.

R has a full outer lower sub-level. (correct)

S has a completely filled outer shell.

S has a higher electron affinity than R.

Which statement correctly explains why element H has a lower first ionisation energy compared to element G?

H's electron configuration is more stable than that of G.

H is a noble gas while G is a transition metal.

H has fewer electrons than G.

G has a half-filled 2p sub-level which is more stable. (correct)

Which of the following explains the trend of increasing electronegativity across a period in the periodic table?

Increasing effective nuclear charge. (correct)

Increasing atomic radius.

Decreasing effective nuclear charge.

Decreasing electron shielding effect.

Which of the following compounds does not contain intermolecular hydrogen bonds?

Hydrogen chloride, HCl Signup and view all the answers

What is the main reason why the boiling point of ammonia is significantly lower than that of water?

Water has stronger hydrogen bonding than ammonia. Signup and view all the answers

What happens to the ionisation energy as you move from left to right across a period?

It increases Signup and view all the answers

Which of the following pairs illustrates an exception to the general trend of ionisation energy in the second period?

Beryllium and Boron Signup and view all the answers

Why is the ionisation energy of Boron less than that of Beryllium?

Boron has a half-filled outer shell Signup and view all the answers

What is the Second Ionisation Energy?

Energy needed to remove an electron from a positively charged ion in gaseous state Signup and view all the answers

What would be expected when removing the first electron from potassium considering its electron configuration?

It requires minimal energy due to the stability of 4s Signup and view all the answers

Why does the second ionisation energy increase significantly after the first electron is removed from potassium?

The remaining electrons experience less shielding Signup and view all the answers

What general trend does the ionisation energy exhibit when an electron is removed from filled subshells?

It increases due to added stability Signup and view all the answers

Which of the following elements would generally have the highest ionisation energy?

Nitrogen Signup and view all the answers

What primarily causes the decrease in electronegativity as you move down a group in the Periodic Table?

Increasing atomic radius Signup and view all the answers

Which trend describes why electronegativity increases across a period?

Decreasing atomic radius Signup and view all the answers

Which group of elements is known for having very low first ionization energy values?

Alkali metals Signup and view all the answers

What is the general reaction of alkali metals with water?

They produce metal hydroxides and hydrogen gas. Signup and view all the answers

As you go down the alkali metal group, which property increases with reactivity?

Screening effect Signup and view all the answers

What product is formed when potassium reacts with oxygen?

Potassium Oxide Signup and view all the answers

What effect does decreasing atomic radius have across a period regarding electronegativity?

It increases electronegativity. Signup and view all the answers

Why do alkali metals not occur free in nature?

They are too reactive and easily form compounds. Signup and view all the answers

What is the primary reason Alkali Metals are stored under oil?

To prevent reaction with oxygen in the air Signup and view all the answers

Which statement accurately describes the trend in reactivity of Alkali Metals?

Reactivity increases as you move down the group Signup and view all the answers

What trend is observed for the electronegativity of Halogens as you move down the group?

Electronegativity decreases Signup and view all the answers

Which Halogen is known to be the most electronegative?

Fluorine Signup and view all the answers

What does the first ionisation energy value of an element represent?

Energy needed to remove the most loosely-bound electron Signup and view all the answers

Why is the first ionisation energy of silicon greater than that of aluminum?

Silicon has a greater nuclear charge Signup and view all the answers

What experimental evidence supports the existence of energy levels in atoms?

Line emission spectrum Signup and view all the answers

What happens to the first ionisation energy as you move from carbon to silicon?

It decreases Signup and view all the answers

What happens to the atomic radius as you move down a group in the Periodic Table?

It increases due to additional energy levels. Signup and view all the answers

Which factor primarily causes the decrease in atomic radius across a period?

Increased effective nuclear charge. Signup and view all the answers

How do atomic radii and ionisation energy trends correlate across a period?

Atomic radii decrease while ionisation energy increases. Signup and view all the answers

Which statement best describes the ionisation energy trend down a group?

It decreases due to increased atomic radius and shielding. Signup and view all the answers

What is the main reason for the increase in the first ionisation energy across a period?

Increase in effective nuclear charge. Signup and view all the answers

What role do inner electrons play in determining the ionisation energy?

They contribute to the screening effect, making outer electrons easier to remove. Signup and view all the answers

What describes the atomic radius and ionisation energy trends as you move from left to right across a period?

Atomic radius decreases while ionisation energy increases. Signup and view all the answers

Which of the following would result in a lower first ionisation energy?

A larger atomic radius. Signup and view all the answers

Study Notes

Atomic Radii Trends

Atomic radius is half the distance between two nuclei of the same atom bonded together.
Atomic radius increases down a group due to increasing energy levels that are further from the nucleus, and the shielding effect of the inner electrons reducing the pull on outer electrons.
Atomic radius decreases across a period due to an increase in effective nuclear charge. The nucleus pulls outer electrons closer, making atoms smaller.

Ionization Energy Trends

First ionization energy is the minimum energy required to remove the most loosely bound electron from a neutral gaseous atom.
Ionization energy decreases down a group because increasing atomic radius means the outermost electrons are further from the attractive force of the nucleus.
Ionization energy increases across a period due to increased effective nuclear charge pulling the outermost electron more strongly, and decreasing atomic radius.
Atoms with half filled or filled outer electron shells require more energy to remove an electron, making them more stable.

Exceptions

There are exceptions to these general trends, particularly in the second period where subtle differences in electron configurations lead to variations in ionization energy. For example, there's a dip in ionization energy between Beryllium and Boron.

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Description

Explore the key concepts of atomic radii and ionization energy trends with this quiz. Understand how these properties change across periods and down groups in the periodic table while examining the underlying principles like effective nuclear charge and energy levels. Test your knowledge on the factors influencing these important atomic characteristics.