IB Chemistry Topic S3.1.4 Trends in Chemical Reactivity Revision Notes (SL/HL)

IB Chemistry Topic S3.1.4 Trends in Chemical Reactivity Revision Notes (SL/HL) | RevisionDojo

Written by official IB examiners

Reactivity Trends in Group 1 (Alkali Metals) and Group 17 (Halogens)

Why Does Reactivity Increase Down Group 1?

The alkali metals are renowned for their high reactivity, which increases as you move down the group.
This trend can be explained by examining ionization energy, the energy required to remove the outermost electron from an atom.
Ionization energy decreases down the group.
1. As you move down Group 1, the atomic radius increases.
2. Each successive element has an additional electron shell, increasing the distance between the nucleus and the valence electron.
3. This greater distance weakens the electrostatic attraction between the nucleus and the outermost electron.
4. Additionally, inner electron shells shield the valence electron from the nucleus’s pull, further reducing ionization energy.
Lower ionization energy means easier electron loss.
1. Alkali metals react by losing their single valence electron to form a positive ion (cation).
2. As it becomes easier to lose this electron, the reactivity of the metal increases.

Example

The reaction between sodium and water vividly demonstrates alkali metal reactivity: $$2\text{Na (s)} + 2\text{H}_2\text{O (l)} \rightarrow 2\text{NaOH (aq)} + \text{H}_2\text{(g)}$$ Here’s what happens:
Sodium loses its valence electron, forming $ \text{Na}^+ $.
Water accepts the electron, releasing hydrogen gas ($ \text{H}_2 $).
Sodium hydroxide ($ \text{NaOH} $) forms, making the solution strongly basic.
Reactions with water become more vigorous as you move down the group.
For instance, potassium reacts explosively compared to sodium.

Applications and Implications of Alkali Metal Reactivity

The high reactivity of alkali metals has significant practical applications but also demands careful handling:

Industrial Use: Sodium and potassium are used in heat transfer systems and the production of compounds like fertilizers.
Safety Concerns: Alkali metals must be stored under oil or in inert atmospheres to prevent reactions with moisture or oxygen in the air.

Nice try, unfortunately this paywall isn't as easy to bypass as you think. Want to help devleop the site? Join the team at https://revisiondojo.com/join-us. exercitation voluptate cillum ullamco excepteur sint officia do tempor Lorem irure minim Lorem elit id voluptate reprehenderit voluptate laboris in nostrud qui non Lorem nostrud laborum culpa sit occaecat reprehenderit

Definition

Paywall

(on a website) an arrangement whereby access is restricted to users who have paid to subscribe to the site.

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.

Duis aute irure dolor in reprehenderit

Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.

Note

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam quis nostrud exercitation.

Excepteur sint occaecat cupidatat non proident

Nemo enim ipsam voluptatem quia voluptas sit aspernatur aut odit aut fugit, sed quia consequuntur magni dolores eos qui ratione voluptatem sequi nesciunt. Neque porro quisquam est, qui dolorem ipsum quia dolor sit amet, consectetur, adipisci velit.

Tip

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.

Lorem ipsum dolor sit amet, consectetur adipiscing elit.
Sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris.
Duis aute irure dolor in reprehenderit in voluptate velit esse cillum.

Unlock the rest of this chapter with a free account

Reactivity Trends in Group 1 (Alkali Metals) and Group 17 (Halogens)

Why Does Reactivity Increase Down Group 1?

The alkali metals are renowned for their high reactivity, which increases as you move down the group.
This trend can be explained by examining ionization energy, the energy required to remove the outermost electron from an atom.
Ionization energy decreases down the group.
1. As you move down Group 1, the atomic radius increases.
2. Each successive element has an additional electron shell, increasing the distance between the nucleus and the valence electron.
3. This greater distance weakens the electrostatic attraction between the nucleus and the outermost electron.
4. Additionally, inner electron shells shield the valence electron from the nucleus’s pull, further reducing ionization energy.
Lower ionization energy means easier electron loss.
1. Alkali metals react by losing their single valence electron to form a positive ion (cation).
2. As it becomes easier to lose this electron, the reactivity of the metal increases.

Example

The reaction between sodium and water vividly demonstrates alkali metal reactivity: $$2\text{Na (s)} + 2\text{H}_2\text{O (l)} \rightarrow 2\text{NaOH (aq)} + \text{H}_2\text{(g)}$$ Here’s what happens:
Sodium loses its valence electron, forming $ \text{Na}^+ $.
Water accepts the electron, releasing hydrogen gas ($ \text{H}_2 $).
Sodium hydroxide ($ \text{NaOH} $) forms, making the solution strongly basic.
Reactions with water become more vigorous as you move down the group.
For instance, potassium reacts explosively compared to sodium.

Applications and Implications of Alkali Metal Reactivity

The high reactivity of alkali metals has significant practical applications but also demands careful handling:

Industrial Use: Sodium and potassium are used in heat transfer systems and the production of compounds like fertilizers.
Safety Concerns: Alkali metals must be stored under oil or in inert atmospheres to prevent reactions with moisture or oxygen in the air.

Definition

Paywall

(on a website) an arrangement whereby access is restricted to users who have paid to subscribe to the site.

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Note

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam quis nostrud exercitation.

Excepteur sint occaecat cupidatat non proident

Tip

Lorem ipsum dolor sit amet, consectetur adipiscing elit.
Sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris.
Duis aute irure dolor in reprehenderit in voluptate velit esse cillum.

Structure 1. Models of the particulate nature of matter5 subtopics

Structure 2. Models of bonding and structure4 subtopics

Structure 3. Classification of matter2 subtopics

Reactivity 1. What drives chemical reactions?4 subtopics

Reactivity 2. How much, how fast and how far?3 subtopics

Reactivity 3. What are the mechanisms of chemical change?4 subtopics

IB Chemistry S3.1.4 Trends in Chemical Reactivity Notes

Structure 1. Models of the particulate nature of matter5 subtopics

Structure 2. Models of bonding and structure4 subtopics

Structure 3. Classification of matter2 subtopics

Reactivity 1. What drives chemical reactions?4 subtopics

Reactivity 2. How much, how fast and how far?3 subtopics

Reactivity 3. What are the mechanisms of chemical change?4 subtopics

Reactivity Trends in Group 1 (Alkali Metals) and Group 17 (Halogens)

Why Does Reactivity Increase Down Group 1?

Applications and Implications of Alkali Metal Reactivity

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Excepteur sint occaecat cupidatat non proident

Unlock the rest of this chapter with a free account

Reactivity Trends in Group 1 (Alkali Metals) and Group 17 (Halogens)

Why Does Reactivity Increase Down Group 1?

Applications and Implications of Alkali Metal Reactivity

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Excepteur sint occaecat cupidatat non proident

Unlock the rest of this chapter with a free account