`overset(24)underset(12)" " Mg and overset(26)underset(12)" " Mg` are symbols of two isotopes of magnesium.
Compare the atoms of these isotopes with respect to :
(i) the composition of their nuclei.
(ii) their electronic configurations.

overset(24)underset(12)" " Mg and overset(26)underset(12)" " Mg are symbols of two isotopes of magnesium. Give reasons why the two isotopes of magnesium have different mass numbers.

From the symbol overset(24)underset(12)" " Mg , state the mass number, the atomic number and electronic configuration of magnesium.

Valency is also the number of electrons - donated or accepted by an atom so as to achieve stable electronic configuration of the nearest noble gas'. With reference to this definition - a] State what is meant by 'stable electronic configuration'. b] State why the valency of- (i) sodium, magnesium & aluminium is +1,+2& +3 respectively. ii] chorine, oxygen & nitroge is: -1, -2 & -3 respectively.

Hydrogen accounts for approximately 75% of the mass of the universe. Hydrogen serves as the nuclear fuel of our Sun and other stars, and these are mainly composed of hydrogen. On the earth, though hydrogen is rarely found in the uncombined state. Since the earth's gravity is too weak to hold such light molecules, nearly all the H_2 originally present in the earth's atmosphere has been lost to space. In the earth's crust and oceans, hydrogen is found in water, petroleum, proteins, carbohydrates and other compounds and it is the ninth most abundant element on a mass basis. Hydrogen has three isotopes : hydrogen or protium (H) , deuterium or heavy hydrogen (D or ), tritium (T or ) . The physical properties of the three isotopes are different due to the difference in their masses, i.e. isotope effect. The chemical properties of the three isotopes are similar as they have the same electronic configuration. Reaction between hydrogen and oxygen is highly exothermic, and gas mixtures that contain as little as 4% by volume hydrogen in oxygen (or in air) are highly flammable and potentially explosive. 2H_(2(g))+O_(2(g)), DeltaH^(ɵ)=-485 kJmol^(-1) As hydrogen is environmentally clean it is an enormously attractive fuel. 'Hydrogen economy' is an emerging field in which it is thought that our energy needs can be met by gaseous, liquid and solid hydrogen. As hydrogen is no a naturally occuring substance such as coal, oil or natural gas, energy must be exploaded to produce hydrogen before it can be used. If an isotope of hydrogen has one neutron in its atom, its atomic number and atomic mass will respectively be

The ubiquitous AM-GM inequality has many applications. It almost crops up in unlikely situations and the solutions using AM-GM are truly elegant . Recall that for n positive reals a_(i) I = 1,2 …, n, the AM-GM inequality tells (overset(n) underset(1)suma_i)/n ge ( overset(n)underset(1)proda_i)^((1)/(n)) The special in which the inequality turns into equality help solves many problems where at first we seem to have not informantion to arrive at the answer . The number of ordered pairs (x,y) pf real numbers satisfying the equation x^(8) + 6= 8 |xy|-y^(8) is

The ubiquitous AM-GM inequality has many applications. It almost crops up in unlikely situations and the solutions using AM-GM are truly elegant . Recall that for n positive reals a_(i) I = 1,2 …, n, the AM-GM inequality tells (overset(n) underset(1)suma_i)/n ge ( overset(n)underset(1)proda_i)^((1)/(n)) The special in which the inequality turns into equality help solves many problems where at first we seem to have not informantion to arrive at the answer . If the equation x^(4) - 4x^(3) + ax^(2) + bx + 1 = 0 has four positive roots , then the value of (|a|+|b|)/(a+b) is

The ubiquitous AM-GM inequality has many applications. It almost crops up in unlikely situations and the solutions using AM-GM are truly elegant . Recall that for n positive reals a_(i) I = 1,2 …, n, the AM-GM inequality tells (overset(n) underset(1)suma_i)/n ge ( overset(n)underset(1)proda_i)^((1)/(n)) The special in which the inequality turns into equality help solves many problems where at first we seem to have not informantion to arrive at the answer . If a,b,c are positive integers satisfying (a)/(b+c)+(b)/(c+a) + (c)/(a+b) = (3)/(2) , then the value of abc + (1)/(abc)

i] Give the IUPAC name of the following organic compounds: A. H-underset(H)underset(|)overset(H)(C)-C-=C-H B. H-underset(H)underset(|)overset(H)overset(|)(C)-overset(O)overset(||)(C)-H ii] What is the special feature of the structure of ethyne. iii] Name the saturated hydrocarbon containing two carbon atoms. iv] Give the structural formula of acetic acid.

The rate of formation of C_(6)H_(6)+3H_(2) underset(k_(b))overset(k_(f))hArr C_(6)H_(12) for the forward reaction is first order with respect to C_(6)H_(6) and H_(12) each. Which one of the options is/are correct?

The rate law expresison is given for a typical reaction, n_(1)A + n_(2) B rarrP as r = k[A]^(n)[B]^(n2) . The reaction completes only in one step and A and B are present in the solution. If the reaction occurs in more than one step, then the rate law is expressed by consdering the slowest step, i.e., for S_(N)l reaction r = k[RX] . If the eraction occurs in more than one step and the rates of the steps involved are comparable, then steady state approximation is conisdered, i.e., the rate of formation of intermediate is always equal to the rate of decompoistion of the intermediate. Conisder the reaction: [[I_(2) underset(k_(1))overset(k_(2))hArr2I("rapid equilibrium")],[H_(2)+2I overset(k_(3))rarr 2HI("slow")]] If we increase the concentration of I_(2) two times, then the rate of formation of HI will