Metals and Non-metals

Comprehensive practice flashcards covering physical and chemical properties of metals and non-metals, the reactivity series, extraction of metals, ionic bonding, corrosion, and alloying.

What is metallic lustre?

The property of metals in their pure state having a shining surface.

What is malleability, and which metals are the most malleable?

Malleability is the ability of metals to be beaten into thin sheets. Gold and silver are the most malleable metals.

What is ductility, and what length of wire can be drawn from one gram of gold?

Ductility is the ability of metals to be drawn into thin wires. Gold is the most ductile metal, and a wire of about $2\,\text{km}$ length can be drawn from $1\,\text{g}$ of gold.

What property of metals is demonstrated by the experimental setup shown in the image?

The setup demonstrates that metals are good conductors of heat and have high melting points.

Which metals are the best conductors of heat, and which are comparatively poor conductors?

The best conductors of heat are silver and copper. Lead and mercury are comparatively poor conductors of heat.

Why are electric wires coated with polyvinylchloride (PVC) or rubber-like materials?

Because metals conduct electricity, and coatings of PVC or rubber-like materials act as electrical insulators to prevent electric shocks.

What property of metals is tested using the electric circuit setup shown in the image?

The circuit tests whether metals conduct electricity (if the bulb glows when a metal sample is placed between terminals A and B, it indicates the metal conducts electricity).

What does the term sonorous mean?

The property of metals that produce a ringing sound when striking a hard surface.

Which metal exists as a liquid at room temperature?

Mercury ($\text{Hg}$).

Which two metals have such low melting points that they will melt if kept on your palm?

Gallium and caesium.

Name a non-metal that has a lustrous appearance.

Iodine.

What are diamond and graphite, and how do their physical properties differ?

They are allotropes of carbon. Diamond is the hardest natural substance known and has very high melting and boiling points, while graphite is a soft conductor of electricity.

Why are alkali metals like lithium, sodium, and potassium kept stored in kerosene oil?

They are soft, highly reactive metals with low densities and melting points that react vigorously and catch fire if exposed to air or water in the open.

What is an amphoteric oxide?

Metal oxides that react with both acids as well as bases to produce salts and water (e.g., aluminium oxide and zinc oxide).

What are the chemical equations showing that aluminium oxide ($\text{Al}_2\text{O}_3$) is amphoteric?

With acid: $\text{Al}_2\text{O}_3 + 6\text{HCl} \rightarrow 2\text{AlCl}_3 + 3\text{H}_2\text{O}$; with base: $\text{Al}_2\text{O}_3 + 2\text{NaOH} \rightarrow 2\text{NaAlO}_2 + \text{H}_2\text{O}$ (producing sodium aluminate).

What is anodising, and how is it carried out?

Anodising is a process of forming a thick protective oxide layer on aluminium. A clean aluminium article is made the anode and electrolysed with dilute sulphuric acid; oxygen evolved at the anode reacts with the aluminium to thicken its oxide layer.

Why does calcium float when added to water?

Calcium reacts less violently with water than sodium or potassium, and the bubbles of hydrogen gas produced stick to the surface of the metal, causing it to float.

What reaction is demonstrated by the apparatus shown in the figure, and what gas is collected?

The action of steam on a metal (such as aluminium, iron, or zinc) producing a metal oxide and hydrogen gas collected over water.

Why is hydrogen gas not evolved when most metals react with nitric acid ($\text{HNO}_3$)?

Because $\text{HNO}_3$ is a strong oxidising agent; it oxidises the $\text{H}_2$ produced to water and is itself reduced to nitrogen oxides ($\text{N}_2\text{O}$, $\text{NO}$, or $\text{NO}_2$).

Which two metals can react with very dilute nitric acid ($\text{HNO}_3$) to evolve hydrogen gas?

Magnesium ($\text{Mg}$) and manganese ($\text{Mn}$).

What is aqua regia, and what is its composition ratio?

Aqua regia (Latin for 'royal water') is a highly corrosive, fuming mixture of concentrated hydrochloric acid and concentrated nitric acid in a $3:1$ ratio that can dissolve noble metals like gold and platinum.

What is the reactivity series of metals?

A list of metals arranged in the order of their decreasing activities, ranging from potassium (most reactive) down to gold (least reactive).

What are ionic or electrovalent compounds?

Compounds formed by the transfer of electrons from a metal (which forms a cation) to a non-metal (which forms an anion), held together by strong electrostatic forces.

Why do ionic compounds have high melting and boiling points?

Because a considerable amount of energy is required to break the strong inter-ionic electrostatic forces of attraction holding the oppositely charged ions together.

Why do ionic compounds conduct electricity in the molten state or aqueous solution but not in the solid state?

In the solid state, ions cannot move due to their rigid crystal structure. In the molten state or solution, the electrostatic attractions are overcome, allowing free movement of ions to conduct electric current.

What are minerals, ores, and gangue?

Minerals are naturally occurring elements or compounds in the earth's crust. Ores are minerals containing a high percentage of a metal from which it can be profitably extracted. Gangue refers to unwanted impurities like soil and sand contaminating mined ores.

What is the difference between roasting and calcination in metallurgy?

Roasting is heating sulphide ores strongly in the presence of excess air to convert them into oxides, whereas calcination is heating carbonate ores strongly in limited air to convert them into oxides.

What reaction is depicted in the image, and what is its industrial application?

The thermit reaction ($\text{Fe}_2\text{O}_3(s) + 2\text{Al}(s) \rightarrow 2\text{Fe}(l) + \text{Al}_2\text{O}_3(s) + \text{Heat}$), used to produce molten iron on-site to weld and join railway tracks or cracked machine parts.

How are metals towards the top of the activity series (such as $\text{Na}$, $\text{Mg}$, and $\text{Ca}$) extracted from their ores?

By electrolytic reduction of their molten chlorides, because their high affinity for oxygen prevents them from being reduced by carbon.

In the electrolytic refining of copper, what materials constitute the anode, cathode, and electrolyte?

The anode is impure copper, the cathode is a thin strip of pure copper, and the electrolyte is an acidified copper sulphate solution.

In the experiment shown investigating iron rusting, what conditions are proven necessary for rust to form?

Both air (oxygen) and water are necessary for iron to rust, as nails only rusted in tube A (exposed to both air and water), but not in B (boiled water without air) or C (dry air with anhydrous calcium chloride).

What is galvanisation?

A method of protecting steel and iron from rusting by coating them with a thin layer of zinc, which remains protective even if the surface coating is scratched or broken.

What is an amalgam?

An alloy in which one of the constituent metals is mercury.

What are the metal compositions of brass, bronze, and solder?

Brass is an alloy of copper and zinc ($\text{Cu}$ and $\text{Zn}$); bronze is an alloy of copper and tin ($\text{Cu}$ and $\text{Sn}$); solder is an alloy of lead and tin ($\text{Pb}$ and $\text{Sn}$).

What ancient metallurgical structure located near the Qutub Minar in Delhi is shown in the image?

The Iron pillar at Delhi, built more than 1600 years ago, standing $8\,\text{m}$ high and weighing $6\,\text{tonnes}$ ($6000\,\text{kg}$), renowned for its rust resistance.