Metals and Their Properties Quiz

Metals and Non-metals

• Everything is made of elements, which can be classified as metals or non-metals based on properties.
• Some elements share properties of both categories and are called semi-metals or metalloids.
• Metals are hard, lustrous, malleable, ductile, and good conductors of heat and electricity.
• Non-metals lack lustre, are poor conductors, brittle, and not malleable or ductile.
• Metals are used in construction (buildings, bridges), coins, utensils, kitchenware, jewellery, and machine parts.
• Non-metals are found in living things' respiration (oxygen), fertilizers (nitrogen), food (carbon, hydrogen, nitrogen, and sulfur), and gunpowder (sulfur).
• Various elements in the body have specific roles like chromium in sugar metabolism, cobalt in vitamin B12, iodine in thyroid function, manganese in bone calcium levels, and copper in red blood cell production.
• Metals have luster due to electrons vibrating when light hits their surface and releasing energy.
• Metals vary in hardness.
• Metals are malleable (can be beaten into thin sheets) and ductile (can be drawn into wires).
• Metals are good conductors of heat.
• Metals are sonorous (produce a sound when struck).
• Non-metals can be solids, liquids, or gases at room temperature, are brittle, non-lustrous, and poor conductors.
• Non-metals include gases like oxygen and nitrogen, and solids like sulfur, phosphorus, and iodine.

Physical Properties of Metals

• Most metals possess metallic lustre (shiny surface).
• Metals are typically hard although there are soft exceptions like sodium and potassium.
• Metals are malleable (can be hammered into thin sheets) and ductile (can be drawn into wires).
• Metals are good conductors of heat and electricity.
• Metals are sonorous (produce a characteristic sound when struck).

Chemical Properties of Metals

• Almost all metals react with oxygen to form metal oxides.
• Metals' reactivity varies, some react violently while others have a slower reaction with oxygen.
• Metals combine with oxygen to form metal oxides.
• Some metals react vigorously with water to produce metal hydroxides and hydrogen gas (e.g., sodium and potassium).
• Reactive metals, like sodium and potassium, react violently enough with water to ignite the hydrogen gas produced.
• Less reactive metals, such as copper and aluminum, need to be heated to react with water.
• Metals react with acids: Many metals react with dilute acids to liberate hydrogen gas, forming the salt of the metal. This reaction is fast for reactive metals and slow for less reactive counterparts.
• Electropositive character: Metals readily lose electrons (e.g., sodium becoming sodium ion).
• Metals act as reducing agents in most chemical reactions.

Chemical Properties of Non-Metals

• Non-metals vary considerably with respect to reactivity.
• Non-metals do not displace hydrogen from acids.
• Non-metals have electronegative character.
• Non-metals form acidic or neutral oxides (e.g., SO2, CO2, P2O5).
• Non-metals act as oxidizing agents in most chemical reactions.

Why are ionic compounds hard?

• Ionic compounds have high melting points and boiling points because the electrostatic forces between oppositely charged ions are strong. Extra energy is needed to break these strong forces of attraction.
• Ionic compounds are brittle and break into pieces at high pressures because these strong forces produce a rigid structure, and any change in that shape will cause the repulsion between like charged ions to make the material break.

Extraction of Metals

• Extraction of metals from their ores is called metallurgy, involving crushing and grinding the ore.
• Concentration of the ore and removal of impurities (gangue) through methods like gravity separation, hydraulic washing, and froth floatation.
• Extracting metal from the concentrated ore involving different strategies based on the metal's reactivity:
  • For high reactivity metals: Electrolysis of their molten or fused oxides or chlorides.
  • For medium reactivity metals: First, convert the ore to oxide then use reduction.
  • For low reactivity metals: Reduction in the presence of excess oxygen (Roasting).
• Refining: Purification of impure metals using methods like electrolysis to get a pure metal.
• Different techniques for refining are employed depending upon the metal.

Corrosion

• Corrosion is the slow degradation of metals due to reaction with oxygen and moisture.
• Corrosion is often a chemical process, such as iron rusting.
• Various methods exist to prevent corrosion. -Painting. -Applying grease or varnish. -Protecting the metal with an alloy that is more resistant to corrosion(galvanizing). -Electroplating with a different metal (e.g., galvanizing or chromium plating). -Cathodic protection: Connecting a more reactive metal to the metal to be protected to displace any interaction with oxygen.