Allied solutions simplified middle school chemistry class 7 Solutions for Chapter 6 metals and non metals

Q1) Give the common name and chemical name of an ore of -

(a) Zinc

(b) Aluminium

(c) Iron

Q2) Distinguish between the physical properties of metals and non-metals with reference to -

(a) lustre (b) malleability (c) ductility (d) tensile strength (e) sonority (f) conduction of heat and electricity (g) melting and boiling point (h) density

Q3) With reference to the physical properties of metals and non-metals, state the following exceptions.

(a) A metals which is liquid at room temperature

(b) A non-metal which sublimes and is non-lustrous.

(c) A non-metal which has low tensile strength

(d) A non-metal which conducts electricity

(e) A metal which floats on water

Q4) With reference to the following metals state their - use in daily life. Metals:

(a) copper (b) iron (c) aluminium (d) magnesium (e) zinc (f) lead (g) silver

Q5) Describe a simple experiment to prove that - a copper wire conducts electricity, but a piece of coal does not.

Q6) Differentiate between metals and non-metals with reference to -

(a) Number of electrons in outer or valence shell (b) formation of cation and anion (c) reaction with dilute acids

Q7) Give a reason why - properties of metals are related to their activity or reactivity series of metals. Explain the same with reference to potassium and iron in the series.

Q8) Give the basic demarcation of the modern periodic table into metals, metalloids and non-metals with special reference to halogens and noble gases .

Q9) Give a reason why the non-metals - halogens and noble gases are placed in separate groups of the periodic table with special reference to their difference in properties.

Q10) State what are metalloids. Name the elements recognised as metalloids. Compare the properties of metalloids with those of metals. State the uses of three different metalloids.

Q11) Explain the term - rusting and give a word equation for the formation of rust. If polished iron nails are kept in three separate test tubes, state the contents in each test tube required, to prove conditions for rusting.

Q12) State why telegraph poles are painted with aluminium paint.

Q13) Give a reason why oiling or greasing is done on the exposed moving iron parts of machinery and not preferred on heavy stationary iron parts.

Q14) State why galvanization, tinning and chrome plating are used as three different processes for coating specific articles for prevention of rusting.

Q15) Give a reason why -

(a) Rust turns moist red litmus blue

(b) A green deposit is seen on the surface of an article of copper

(c) Iron objects rust easily but the iron pillar at Qutub Minar has not rusted over the years.

Q16) State a specific reason for using -

(a) Steel in automobiles

(b) Gold in jewellery

(c) Copper in electrical cables

(d) Zinc in galvanizing

(e) Lead in bullets

(f) Magnesium in fireworks

Q1) Complete the statements given below, by filling in the blank with the correct word/s:

1. The ability of a metal to produce a reasonant sound _______.

2. A metal which floats on water _______.

3. A non-metal that leaves a mark on paper _______.

4. A non-metal which allows an electric current to pass through it_______.

5. A non-metal added to swimming pools to kill germs _______.

Q2) Give reasons for the following:

1. Metals form cations while non-metals form anions.
2. Potassium reacts vigorously with cold water while copper does not react with water or steam.
3. Rusting reduces the structural strength of iron.
4. A suspension of rust is basic in nature.
5. Galvanized steel is not used for articles for edible applications .

Q3) Name the following :

1. The most reactive halogen

2. A meatl used in packaging

3. The chemical compound responsible for the green deposit on the surfaced of articles of copper.

4. A metal used in flexible pipes

5. A halogen which is solid at room temperature.

Q4) Match the correct answer from A, B, C, D and E - for each statement given below:

A : Boron, B : Chlorine, C : Potassium, D : Platinum, E : Radon

1. The element placed in the extreme left of the Modern Periodic Table.

2. The element which shows properties of both metals and non - metals.

3. The element from the halogen family which is most abundant.

4. The element which is nob;e gas and radioactive in nature.

5. The element which is a noble metal.

Q5) State whether the statements given below are true or false. If false, write the correct statement.

1. Lead pencils contain lead.

2. The chemical name of rust is iron [[III]] oxide.

3. Silicon is an example of a metalloid.

4. Either oxygen or moisture is essential for rusting.

5. Graphite is a lustrous non-metal which conducts electricity.