What are the major differences between metals and non-metals?
METALS |
NON METALS |
Metals can lose electrons easily. |
Non-metals cannot lose electrons easily |
Metals are solids at room ( Exceptions – Hg, Ga ). |
temperature Non – metals may be solids, liquids or gases at room temperature |
Metals generally form ionic compounds. |
Non–metals generally form covalent compounds. |
Metals have low ionization enthalpies. |
Non–metals have high ionization enthalpies. |
Metals are less electronegative. They are rather electropositive elements. |
Non–metals are electronegative. |
Metals have a high reducing power. |
Non–metals have a low reducing power |
Metals have luster. They reflect light from polished or freshly cut surface |
Non-metals do not have luster.( Exceptions – Diamond and Iodine ) |
Metals generally have high density |
Non-metals generally have low density |
They are good conductors of heat and and electricity.
|
They are usually bad conductors of heat electricity. (exception – carbon in the form of gas carbon and graphite ) |
Metals are malleable and ductile. They can be beaten into sheets and drawn into wires. |
Non-metals are not malleable and ductile They are brittle when solid.They can be crushed into powder |
They have a three dimensional crystal structure with metallic bonds |
They have different types of structures with covalent and van-der-Walls’ bonds |
Metals usually have high tensile Strength |
Non- metals usually have low tensile strength |
Metals generally have 1 to 3 electrons in outermost shell of their atoms |
Non-metals generally have 4 to 8 in their outermost shell of the atom |
They generally form basic oxides. |
They generally form acidic oxides |
They act as reducing agents |
They act as oxidizing agents. |
Write the general outer electronic configuration of s-, p-, d- and f- block elements.
Considering the elements B, Al, Mg, and K, the correct order of their metallic character is:
(a) B > Al > Mg > K
(b) Al > Mg > B > K
(c) Mg > Al > K > B
(d) K > Mg > Al > B
What do you understand by isoelectronic species? Name a species that will be isoelectronic with each of the following atoms or ions.
(i) F–
(ii) Ar
(iii) Mg2+
(iv) Rb+
What is the basic difference between the terms electron gain enthalpy and electronegativity?
Considering the elements B, C, N, F, and Si, the correct order of their non-metallic character is:
(a) B > C > Si > N > F
b) Si > C > B > N > F
(c) F > N > C > B > Si
d) F > N > C > Si > B
Assign the position of the element having outer electronic configuration
(i) ns2 np4 for n = 3 (ii) (n - 1)d2 ns2 for n = 4, and (iii) (n - 2) f7 (n - 1)d1 ns2 for n = 6, in the periodic table.
How does atomic radius vary in a period and in a group? How do you explain the variation?
Use the periodic table to answer the following questions.
(a) Identify an element with five electrons in the outer subshell.
(b) Identify an element that would tend to lose two electrons.
(c) Identify an element that would tend to gain two electrons.
(d) Identify the group having metal, non-metal, liquid as well as gas at the room temperature.
Considering the elements F, Cl, O and N, the correct order of their chemical reactivity in terms of oxidizing property is:
(a) F > Cl > O > N
(b) F > O > Cl > N
(c) Cl > F > O > N
(d) O > F > N > Cl
On the basis of quantum numbers, justify that the sixth period of the periodic table should have 32 elements.
How do you account for the formation of ethane during chlorination of methane?
What are hybridisation states of each carbon atom in the following compounds ?
(i) CH2=C=O,
(ii) CH3CH=CH2,
(iii) (CH3)2CO,
(iv) CH2=CHCN,
(v) C6H6
What will be the minimum pressure required to compress 500 dm3 of air at 1 bar to 200 dm3 at 30°C?
What are the common physical and chemical features of alkali metals?
Calculate the molecular mass of the following:
(i) H2O
(ii) CO2
(iii) CH4
Assign oxidation number to the underlined elements in each of the following species:
(a) NaH2PO4
(b) NaHSO4
(c) H4P2O7
(d) K2MnO4
(e) CaO2
(f) NaBH4
(g) H2S2O7
(h) KAl(SO4)2.12 H2O
Explain the formation of a chemical bond.
Choose the correct answer. A thermodynamic state function is a quantity
(i) used to determine heat changes
(ii) whose value is independent of path
(iii) used to determine pressure volume work
(iv) whose value depends on temperature only.
A liquid is in equilibrium with its vapour in a sealed container at a fixed temperature. The volume of the container is suddenly increased.
a) What is the initial effect of the change on vapour pressure?
b) How do rates of evaporation and condensation change initially?
c) What happens when equilibrium is restored finally and what will be the final vapour pressure?
Justify the position of hydrogen in the periodic table on the basis of its electronic configuration.
Calculate the pH of the following solutions:
(a) 2 g of TlOH dissolved in water to give 2 litre of solution.
(b) 0.3 g of Ca(OH)2 dissolved in water to give 500 mL of solution.
(c) 0.3 g of NaOH dissolved in water to give 200 mL of solution.
(d) 1mL of 13.6 M HCl is diluted with water to give 1 litre of solution.
(i) Calculate the number of electrons which will together weigh one gram.
(ii) Calculate the mass and charge of one mole of electrons.
The reaction,
CO(g) + 3H2(g) ↔ CH4(g) + H2O(g)
is at equilibrium at 1300 K in a 1L flask. It also contain 0.30 mol of CO, 0.10 mol of H2 and 0.02 mol of H2O and an unknown amount of CH4 in the flask. Determine the concentration of CH4 in the mixture. The equilibrium constant, Kc for the reaction at the given temperature is 3.90.
Calculate the energy required for the process
The ionization energy for the H atom in the ground state is 2.18 ×10–18 J atom–1
What are allotropes? Sketch the structure of two allotropes of carbon namely diamond and graphite. What is the impact of structure on physical properties of two allotropes?
Ionic product of water at 310 K is 2.7 x 10-14. What is the pH of neutral water at this temperature?
Arrange benzene, n-hexane and ethyne in decreasing order of acidic behaviour. Also give reason for this behaviour.
What is Kc for the following equilibrium when the equilibrium concentration of each substance is: [SO2]= 0.60 M, [O2] = 0.82 M and [SO3] = 1.90 M ?
2SO2(g) + O2(g) ↔ 2SO3(g)
At 473 K, equilibrium constant Kc for decomposition of phosphorus pentachloride, PCl5 is 8.3 ×10-3. If decomposition is depicted as,
PCl5 (g) ↔ PCl3 (g) + Cl2 (g) ΔrH0 = 124.0 kJ mol–1
(a) write an expression for Kc for the reaction.
(b) what is the value of Kc for the reverse reaction at the same temperature ?
(c) what would be the effect on Kc if (i) more PCl5 is added (ii) pressure is increased (iii) the temperature is increased ?
The concentration of hydrogen ion in a sample of soft drink is 3.8 × 10–3 M. what is its pH?