Alkali Metals (Group 1): Properties and Reactions

Flashcards covering Group 1 alkali metals: elements in Group 1, their single outer electron, shared properties, trends down the group, ion formation, reactions with water, chlorine, and oxygen, comparisons to transition metals, and safety notes.

What are Group 1 elements collectively known as?

Alkali metals.

Which elements are in Group 1?

Lithium, sodium, potassium, rubidium, caesium, and francium.

How many electrons are in the outer shell of Group 1 elements?

One electron.

What common properties do alkali metals share?

They are soft, highly reactive, and have low density.

What is the trend in reactivity as you go down Group 1?

Reactivity increases down the group.

What happens to melting and boiling points as you go down Group 1?

They decrease (lower melting and boiling points).

What happens to relative atomic mass as you go down Group 1?

It increases (higher relative atomic mass).

What ions do Group 1 metals form when reacting with non-metals?

1+ ions.

What is the appearance and solubility of Group 1 ionic compounds with non-metals in water?

They are white solids that dissolve in water to form colorless solutions.

What is the general reaction of a Group 1 metal with water?

2 M + 2 H2O → 2 MOH + H2 (metal hydroxide and hydrogen gas).

Which Group 1 metal's reaction with water can ignite hydrogen?

Potassium.

What compound forms when Group 1 metals react with chlorine gas?

White metal chloride salts (e.g., NaCl).

How does reactivity with chlorine change down Group 1?

As you go down the group, reactivity increases and the reaction becomes more vigorous.

What oxides do lithium, sodium, and potassium form when they react with oxygen?

Lithium forms Li2O; sodium forms Na2O and Na2O2; potassium forms K2O2 and KO2.

Why do Group 1 metals tarnish in air?

They react with oxygen to form a dull metal oxide layer.

How do Group 1 metals compare to transition metals in terms of reactivity and physical properties?

Group 1 metals are more reactive, less dense, softer, and have lower melting points than many transition metals (e.g., Mn melts ~2000°C vs Na ~98°C).

What safety considerations are mentioned for alkali metal reactions?

Reactions can fizz and may explode; safety precautions are required.