Metal Elements Overview

25min Part 3 / Ch6 / Lesson 1

Prerequisites: 1-2-6

Objectives

Understand the activity series and metal reactivity
Describe properties of alkali and alkaline earth metals
Know characteristics of transition metals

Activity Series (Ionization Tendency)

Activity series: metals ranked by how easily they form cations in aqueous solution.

$\mathrm{Li > K > Ca > Na > Mg > Al > Zn > Fe > Ni > Sn > Pb > (H_2) > Cu > Hg > Ag > Pt > Au}$

Reactivity	Metals	With water	With acids
Very high	Li, K, Ca, Na	React with cold water	React vigorously
High	Mg, Al, Zn, Fe	React with steam	React with dilute acid
Low	Cu, Hg, Ag	No reaction	Only oxidizing acids
Very low	Pt, Au	No reaction	Only aqua regia

Alkali Metals (Group 1: Li, Na, K)

Alkali metal characteristics:

Soft metals (can be cut with a knife)
Low density (Li, Na, K float on water)
React vigorously with water producing hydrogen (Na + H₂O → NaOH + ½H₂↑)
Show characteristic flame colors (Li: red, Na: yellow, K: violet)

Alkaline Earth Metals (Group 2: Ca, Sr, Ba)

Harder and denser than alkali metals
React with water (Ca reacts gently at room temperature)
Flame colors: Ca: orange-red, Sr: crimson, Ba: yellow-green

Transition Metals

Transition metal characteristics:

Exhibit multiple oxidation states (e.g., Fe²⁺, Fe³⁺)
Form colored compounds
Many serve as catalysts
Key examples: Fe, Cu, Zn, Ag, Au, Pt

Colors of iron compounds:

Ion/Compound	Color
$\mathrm{Fe^{2+}}$ (aq)	Pale green
$\mathrm{Fe^{3+}}$ (aq)	Yellow-brown
$\mathrm{Fe(OH)_2}$	White (→ green → red-brown on oxidation)
$\mathrm{Fe(OH)_3}$	Red-brown

Colors of copper compounds:

Compound	Color
$\mathrm{Cu^{2+}}$ (aq)	Blue
$\mathrm{CuSO_4 \cdot 5H_2O}$	Blue crystals
$\mathrm{CuSO_4}$ (anhydrous)	White
$\mathrm{Cu(OH)_2}$	Blue-white

Check Your Understanding

Q1 Which metal reacts with dilute HCl to produce hydrogen?

Q2 What is the flame color of sodium?

Q3 Which is NOT a characteristic of transition metals?

Exercises

Q1. Arrange in order of decreasing activity: Cu, Zn, Fe, Ag, Na

Solution

$\mathrm{Na > Zn > Fe > Cu > Ag}$

From the activity series: Na (alkali metal) is most active, followed by Zn > Fe > Cu > Ag.

Q2. What happens when an iron nail is placed in copper(II) sulfate solution? Write the equation and explain.

Solution

$\mathrm{Fe + CuSO_4 \rightarrow FeSO_4 + Cu}$

Iron is more active than copper (higher in the activity series), so Fe dissolves as $\mathrm{Fe^{2+}}$ while $\mathrm{Cu^{2+}}$ is reduced to metallic Cu, which deposits on the nail surface as a reddish-brown coating.