plzz help me solve this "assignment no 3"
write down the names of all the elements present in group 1,2,3.learn the elements of
of period 2 with their atomic number and atomic masses
Answers
Answer:
Hope this helps. Please follow and mark as Brainliest. :-):-)Thank you.
Explanation:
The following collective names are recommended by IUPAC:
Alkali metals – The metals of group 1: Li, Na, K, Rb, Cs, Fr.
Alkaline earth metals – The metals of group 2: Be, Mg, Ca, Sr, Ba, Ra.
Transition elements – Elements in groups 3 to 11 or 3 to 12.
Assignment no. 1:
1-The number of protons in a atom of an element decides its atomic number. It also helps in defining one's electronic configuration. Since, number of electrons and protons of an element is equal to its atomic number.
E.g. (²³₁₁Na)-Sodium has an atomic number of 11.
(²⁴₁₂Mg)-Magnesium has an atomic number of 12.
2-Atomic mass of an element is defined as the sum of the number of protons and neutrons in an atom of that element. It is generally measured in u/amu.
E.g. (¹₁H)-Hydrogen has an atomic mass of 1u.
(²⁰₁₀F)-Fluorine has an atomic mass of 20u.
3-An element is a pure substance composed of only single kind of atoms. Its constituents are atoms.
E.g. Silver(Ag), Gold(Au) are some examples of element.
4-Compounds are those pure substance that are composed of more than one kind of atoms or molecules. These atoms combine chemically together to form compounds. They consist of atoms in a fixed proportion.
E.g. Water(H₂O), Ammonia(NH₃) are few examples of compounds.
5-Mixtures are impure substances that consists of various atoms/molecules/matter physically mixed together in amy ratio.
E.g. Soil, Air are mixtures.
Assignment no. 2:
1- (i) Atoms are the fundamental unit of any element. They define the properties and structure of an element to which they belong.
(ii) These are generally unstable as itself.
(iii) Atoms are composed of even smaller particles such as electrons, protons and neutrons. But they cannot be separated into them easily.
(i) Molecules are the fundamental unit of any compound. Thus defining their properties.
(ii) Molecules are stable form of combined atoms in a fixed proportion.
(ii) Generally, Molecules can be broken into its constituents (atoms) by various chemical reactions.
2-Solutions that consists of its solute in a such large quantity that no more solute could be dissolved into it is called as saturated soution.
E.g. A mixture of 100g of sugar in 50mL of water such that no more sugar can dissolved into it.
Solutions that consists of solute in less amount than its capability to dissolve any solute is an unsaturated solution.
E.g. A mixture of 1g of salt in 100mL of water.
3-
Solids
(i) Fixed volume
(ii) Fixed shape
(iii) Least rate of diffusion
(iv) Least movement or kinetic energy of particles.
(v) Rigid in nature
(vi) Least spaces between particles.
(vii) High Intermolecular attraction.
(viii) Least Compressible
(ix) Least expansion on heating
(x) High density.
(xi) E.g. A Brick, A Stone, etcetera.
Liquids
(i) Fixed volume
(ii) No Fixed shape
(iii) Intermediate rate of diffusion
(iv) Intermediate level of movement or kinetic energy of particles.
(v) Fluids in nature
(vi) Intermediate spaces between particles.
(vii) intermediate Intermolecular attraction.
(viii) compressible upto some extent
(ix) Intermediate expansion on heating
(x) Intermediate density.
(xi) E.g. Water, Liquid nitrogen, etcetera.
Gases
(i) Unfixed volume
(ii) Unfixed shape
(iii) High rate of diffusion
(iv) High movement or kinetic energy in particles.
(v) Fluid in nature
(vi) High spaces between particles.
(vii) Low Intermolecular attraction.
(viii) Highly compressible
(ix) High expansion on heating
(x) Low density.
(xi) E.g. Nitrogen gas, Hydrogen gas, etcetera.
Assignment No. 3
Period-1
Hydrogen-H
Lithium-Li
Sodium-Na
Potassium-K
Rubidium-Rb
Caesium-Cs
Francium-Fr
Period-2
Beryllium-⁹₄Be
Magnesium-²⁴₁₂Mg
Calcium-⁴⁰₂₀Ca
Strontium-⁸⁸₃₈Sr
Barium-¹³⁷₅₆Ba
Radium-²²⁶₈₈Ra
Period-IIIA
Boron-B
Aluminum-Al
Gallium-G
Indium-In
Thallium-Tl
Nihonium-Nh
Period-IIIB
Scandium-Sc
Yttrium-Y
Lanthanum-La
Actinium-Ac