# Basic Concepts of Chemistry for MH-CET/ NEET

Published On: 3/28/2023
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What is Measurement unit for Atomic Wight?

Atomic weight is measured in atomic Mass Unit (amu) , also called as daltons.

What is Relative Atomic Mass?

Atomic weight is also called as relative atomic mass of chemical element’s atoms to some standard

What is Molecular Mass / Atomic Mass?

Since 1961 the standard unit of atomic mass has been one-twelfth the mass of an atom of isotope carbon-12

Molecular Mass = Average relative Mass of one Molecule / (1/12 X mass of C-12 Atom)

Atomic Mass = Average relative Mass of one Atom / (1/12 X mass of C-12 Atom)

The original standard of atomic weight, established in the 19th century, was hydrogen, with a value of 1.

From about 1900 until 1961, oxygen was used as the reference standard, with an assigned value of 16. The unit of atomic mass was thereby defined as 1/16 the mass of an oxygen atom.

What is isotope?

An isotope is one of two or more species of atoms of the same chemical element that have different atomic mass numbers (protons + neutrons)

Who is john Dalton?

John Dalton developed a crude method for measuring the masses of the elements in a compound.

His law of multiple proportions states that when two elements form more than one compound, masses of one element that combine with a fixed mass of the other are in a ratio of small whole numbers.

What is valency?

A measurement of the power of an atom to combine with others, by the number of hydrogen atoms it can combine with or take the place of.

What is equivalent weight?

The equivalent weight of an element is its gram atomic weight divided by its valence (combining power).

Equivalent Weight = Molecular weight/ Valency

What is Molality and its formula?

Molality (m) is defined as the number of moles of solute per kilogram of solvent.

Formula Molality (m) = moles of solute / kilograms of solvent

What is Molarity and its formula?

Molarity means solution concentration i.e. the amount of solute in moles divided by the volume of solution in liters

M = moles of solute/liters of solution

What is equivalent weight of acid?

The equivalent weight of an acid is the mass of acid required to generate one mole of hydrogen (hydronium) ion in aqueous solution.

Equivalent weight of acid= Molecular Mass / Basicity

What is equivalent weight of base?

The equivalent weight of base is the weight of compound that contains one equivalent of hydroxide ion (OH-)

Equivalent weight of acid= Molecular Mass / Acidity

### Periodic Table for Elements with Atomic Mass, symbol, atomic number and classification.

element symbol atomic number atomic weight Classification
hydrogen H 1[1.00784, 1.00811] Halogen
helium He 24.002602Nobel Gas
lithium Li 3[6.938, 6.997] Alkali Metal
beryllium Be 49.0121831Alkaline Earth
boron B 5[10.806, 10.821] Metalloid
carbon C 6[12.0096, 12.0116] Non metal
nitrogen N 7[14.00643, 14.00728] Non Metal
oxygen O 8[15.99903, 15.99977] Non Metal
fluorine F 918.998403163Halogen
neon Ne 1020.1797Nobel Gas
sodium Na 1122.98976928Alkali Metal
magnesium Mg 12[24.304, 24.307] Alkaline Earth
aluminum (aluminium) Al 1326.9815385Basic Metal
silicon Si 14[28.084, 28.086] Metalloid
phosphorus P 1530.973761998Non metal
sulfur (sulphur) S 16[32.059, 32.076] Non metal
chlorine Cl 17[35.446, 35.457] Halogen
argon Ar 1839.948Nobel Gas
potassium K 1939.0983Alkali Metal
calcium Ca 2040.078Alkaline Earth
scandium Sc 2144.955908Transition Metal
titanium Ti 2247.867Transition Metal
chromium Cr 2451.9961Transition Metal
manganese Mn 2554.938044Transition Metal
iron Fe 2655.845Transition Metal
cobalt Co 2758.933194Transition Metal
nickel Ni 2858.6934Transition Metal
copper Cu 2963.546Transition Metal
zinc Zn 3065.38Transition Metal
gallium Ga 3169.723Basic Metal
germanium Ge 3272.63Metalloid
arsenic As 3374.921595Metalloid
selenium Se 3478.971Non metal
bromine Br 35[79.901, 79.907] Halogen
krypton Kr 3683.798Nobel Gas
rubidium Rb 3785.4678Alkali Metal
strontium Sr 3887.62Alkaline Earth
yttrium Y 3988.90594Transition Metal
zirconium Zr 4091.224Transition Metal
niobium Nb 4192.90637Transition Metal
molybdenum Mo 4295.95Transition Metal
technetium Tc 4397Transition Metal
ruthenium Ru 44101.07Transition Metal
rhodium Rh 45102.9055Transition Metal
silver Ag 47107.8682Transition Metal
indium In 49114.818Basic Metal
tin Sn 50118.71Basic Metal
antimony Sb 51121.76Metalloid
tellurium Te 52127.6Metalloid
iodine I 53126.90447Halogen
xenon Xe 54131.293Nobel Gas
cesium (caesium) Cs 55132.90545196Alkali Metal
barium Ba 56137.327Alkaline Earth
lanthanum La 57138.90547Lanthanide
cerium Ce 58140.116Lanthanide
praseodymium Pr 59140.90766Lanthanide
neodymium Nd 60144.242Lanthanide
promethium Pm 61145Lanthanide
samarium Sm 62150.36Lanthanide
europium Eu 63151.964Lanthanide
terbium Tb 65158.92535Lanthanide
dysprosium Dy 66162.5Lanthanide
holmium Ho 67164.93033Lanthanide
erbium Er 68167.259Lanthanide
thulium Tm 69168.93422Lanthanide
ytterbium Yb 70173.045Lanthanide
lutetium Lu 71174.9668Lanthanide
hafnium Hf 72178.49Transition Metal
tantalum Ta 73180.94788Transition Metal
tungsten (wolfram) W 74183.84Transition Metal
rhenium Re 75186.207Transition Metal
osmium Os 76190.23Transition Metal
iridium Ir 77192.217Transition Metal
platinum Pt 78195.084Transition Metal
gold Au 79196.966569Transition Metal
mercury Hg 80200.592Transition Metal
thallium Tl 81[204.382, 204.385] Basic Metal
bismuth Bi 83208.9804Basic Metal
polonium Po 84209Metalloid
astatine At 85210Halogen
francium Fr 87223Alkali Metal
actinium Ac 89227Actinide
thorium Th 90232.0377Actinide
protactinium Pa 91231.03588Actinide
uranium U 92238.02891Actinide
neptunium Np 93237Actinide
plutonium Pu 94244Actinide
americium Am 95243Actinide
curium Cm 96247Actinide
berkelium Bk 97247Actinide
californium Cf 98251Actinide
einsteinium Es 99252Actinide
fermium Fm 100257Actinide
mendelevium Md 101258Actinide
nobelium No 102259Actinide
lawrencium Lr 103262Actinide
rutherfordium Rf 104263Transition Metal
dubnium Db 105268Transition Metal
seaborgium Sg 106271Transition Metal
bohrium Bh 107270Transition Metal
hassium Hs 108270Transition Metal
meitnerium Mt 109278Transition Metal
roentgenium Rg 111281Transition Metal
copernicium Cn 112285Transition Metal
ununtrium Uut 113286Basic Metal
flerovium Fl 114289Basic Metal
ununpentium Uup 115289Basic Metal
livermorium Lv 116293Basic Metal
ununseptium Uus 117294Halogen
ununoctium Uuo 118294Nobel Gas

Elements with an atomic weight given in square brackets have an atomic weight that is given as a range.

Reference
https://www.britannica.com/science/atomic-weight
https://sciencenotes.org/periodic-table-with-atomic-mass/

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