NCERT Solution for Class Tenth Science Chapter 3
Metals and Non-metals
CBSE NCERT Book Session-2022-2023
Exercises Questions
Page No-21
Questions No-14
Differentiate between metal and non-metal on the basis of their chemical properties.
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Metal:
1. Metals are electropositive.
2. They react with oxygen to form basic oxides. 4Na + O₂ → 2Na₂ 0 These have ionic bonds.
3. They react with water to form oxides and hydroxides. Some metals react with cold water, some with hot water, and some with steam.
2𝑁𝑎+2𝐻₂𝑂 → 2𝑁𝑎𝑂𝐻+𝐻₂↑
3. They react with dilute acids to form a salt and evolve hydrogen gas. However, Cu, Ag, Au, Pt, Hg do not react.
2𝑁𝑎+2𝐻𝐶𝑙 → 2𝑁𝑎𝐶𝑙+𝐻₂↑
4.They react with the salt solution of metals. Depending on their reactivity, displacement reaction can occur.
2𝐶𝑢𝑆𝑂₄+𝑍𝑛 → 𝑍𝑛𝑆𝑂₄+𝐶𝑢
5. They act as reducing agents (as they can easily lose electrons).
Na → Na⁺+e⁻
Non-metals:
1. Non-metals are electronegative.
2. They react with oxygen to form acidic or neutral oxides.
𝐶+𝑂₂ → C0₂ These have covalent bonds.
3. They do not react with water.
4. They do not react with dilute acids. These are not capable of replacing hydrogen.
5. These react with the salt solution of non-metals.
6. These act as oxidising agents (as they can gain electrons).
Cl₂+2e ⁻ →Cl
Metals
(i) Metals form basic oxides or amphoteric oxides.
(ii) Metals replace hydrogen from acids and form salts.
(iii) With chlorine, metals form chlorides which are electrovalent.
(iv) With hydrogen few metals form hydrides which are electrovalent.
Non-metals
(i) Non-metals form acidic or neutral oxides.
(ii) Non-metals do not replace hydrogen from acids.
(iii) With chlorine, non-metals form chlorides which are covalent.
(iv) With hydrogen, non-metals form many stable hydrides which are covalent.
Metals and non-metals can be differentiated based on their chemical properties. Here are some key distinctions between the two groups:
1. Metallic Character vs. Non-Metallic Character:
. Metals tend to exhibit metallic character, which includes properties like malleability, ductility, high electrical and thermal conductivity, and a shiny luster.
. Non-metals lack metallic character and often have opposite properties, such as brittleness, lack of ductility and malleability, poor electrical and thermal conductivity, and a dull appearance.
2. Electronegativity:
. Metals generally have low electronegativity values, meaning they have a tendency to lose electrons in chemical reactions to form positively charged ions (cations).
. Non-metals have higher electronegativity values, indicating their tendency to gain electrons in chemical reactions to form negatively charged ions (anions).
3. Formation of Oxides:
. Metals typically form basic or alkaline oxides when they react with oxygen. These oxides can neutralize acids and produce basic solutions when dissolved in water.
Non-metals usually form acidic oxides when they react with oxygen. These oxides can acidify water and produce acidic solutions when dissolved.
4. Reaction with Acids:
. Metals react with acids to produce salt and hydrogen gas. For example, the reaction of zinc with hydrochloric acid:
Zn(s) + 2HCl(aq) → ZnCl2(aq) + H2(g)
. Non-metals, with some exceptions like hydrogen, do not typically react with acids.
5. Ion Formation:
. Metals tend to lose electrons to form positively charged ions (cations). For example, sodium (Na) forms Na⁺ ions by losing one electron.
. Non-metals tend to gain electrons to form negatively charged ions (anions). For example, chlorine (Cl) forms Cl⁻ ions by gaining one electron.
6. Corrosion:
. Metals are susceptible to corrosion in the presence of oxygen and moisture. This corrosion often results in the formation of metal oxides.
. Non-metals do not undergo typical corrosion but may undergo other forms of degradation or chemical reactions, depending on the specific non-metal and conditions.
These are some of the fundamental differences in the chemical properties of metals and non-metals. These distinctions play a crucial role in understanding how these elements interact with each other and with other substances in various chemical reactions.