Chemistry
Periodic Classification and Elements
1,176 Questions
Periodic classification organizes chemical elements based on atomic structure, periodic laws, and elemental properties. It covers historical classification systems, electron configurations, and periodic trends. Test takers preparing for chemistry sections will find these questions crucial for mastering fundamental element properties and atomic interactions.
Periodic table structureAtomic orbitalsElement identificationPeriodic laws
Periodic Classification and Elements Questions
C
Correct answer
Explanation
The periodic table is organized into 7 horizontal rows, which are known as periods. These correspond to the principal energy levels of the atoms.
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Tungsten (W)
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Iron (Fe)
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Sodium (Na)
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Potassium (K)
C
Correct answer
Explanation
Sodium has the symbol Na, which comes from the Latin word natrium. Among the options, Sodium has the lowest atomic number (11).
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p > sp3 > sp2 > sp > s
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p > s > sp > sp2 > sp3
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sp3 > sp2 > sp > p > s
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sp > sp2 > sp3 > p > s
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s > sp > sp2 > sp3 > p
A
Correct answer
Explanation
p - orbital has maximum energy than hybrid orbital and s - orbital has lower energy than hybrid orbital.
In case of hybrid orbital, sp3 have more p character than sp2 and sp2 have more p character than sp.
So, the decreasing order of orbitals is p > sp3 > sp2 > sp > s.
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A = 2, 8, 8
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B = 2, 8, 4
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C = 2, 8, 8, 1
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D = 2, 8, 8, 7
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E = 2, 8, 8, 5
C
Correct answer
Explanation
Metallic character ∝ 1/(No. of e- in outermost shell)
Element C has 1 electron in outermost shell, so it has most metallic character.
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principal quantum number
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type of electron
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nuclear charge
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type of bonding in crystal lattice
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principal quantum number
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atomic number
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atomicity
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atomic weight
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molecule
B
Correct answer
Explanation
Atomicity refers to the total number of atoms present in one molecule of an element. For example, oxygen has an atomicity of 2 (O2).
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lanthanides
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metals
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non-metals
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halogens
D
Correct answer
Explanation
Fluorine, chlorine, bromine, and iodine belong to Group 17 of the periodic table, which are collectively known as the halogens. They are highly reactive non-metals.
D
Correct answer
Explanation
This option is correct because the number of electrons in the ‘p’ orbital is greater than the half the capacity of this orbital. So, the greater the J value, the lower the energy. Thus, the spectroscopic term symbol for the ground state of a fluorine atom is 2P3/2.
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Increasing atomic masses
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Increasing atomic numbers
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Metals and Non Metals
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Decreasing atomic masses
C
Correct answer
Explanation
Elements were first classified into metals and non metals
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Oxygen and hydrogen were his favourite elements .
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Oxygen and hydrogen are gases.
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Oxygen and hydrogen were highly reactive in nature and formed compounds with almost every element.
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Oxygen and hydrogen were old elements.
C
Correct answer
Explanation
oxygen and hydrogen are very reactive in nature and formed compounds with almost every element
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6 , 8.
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9, 7.
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6 , 7.
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7 , 6.
B
Correct answer
Explanation
mendeleevs' periodic table contained 8 groups and 6 periods
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Atomic size increases
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Atomic size decreases
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No change in atomic size
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Atomic size first increases and then decreases
B
Correct answer
Explanation
when we go from left to right in a period the effective nuclear charge of an atom increases and therefore the attraction between the nuclear charge and the shells(electrons) increases hence the atomic size of an atom decreases
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Atomic number
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Valence shells
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Atomic masses
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As per his wish
C
Correct answer
Explanation
criteria used by mendeleev in creating his periodic table is atomic masses
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N , O , C
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Ca , Ba, Sr
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H , He, Li
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Ca, Sr , Ba
D
Correct answer
Explanation
as per dobereiners law , the middle element should be the average of the other two elements
therefore Ca, Sr , Ba is the proper set of elements which satisfy dobereiners law
C
Correct answer
Explanation
there are 18 groups in the long form of the periodic table