Chemistry
Periodic Classification and Elements
1,092 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
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pisidium
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podium
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pevelium
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rhodium
A
Correct answer
Explanation
Pisidium is a genus of very small freshwater clams, with some species having shells measuring only 1-2mm, making them among the smallest shells in the world. The other options are either misspellings or incorrect terms: rhodium is a chemical element, not a shell.
B
Correct answer
Explanation
Electron configuration of Fe: [Ar] 3d6 4s2. If 2 electrons are removed then number of electrons left would be 6 and thus, there would be 4 unpaired electrons.
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molecule
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nucleus
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atom
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matter
C
Correct answer
Explanation
An atom is the smallest unit of an element that retains its chemical properties and can participate in chemical reactions. A molecule consists of two or more atoms bonded together. The nucleus is just the central part of an atom, while matter is a general term for anything that has mass and occupies space.
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in between s- and p-block elements
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like that of p- and d-block elements
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members of I – A group
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like inactive elements
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like active elements
A
Correct answer
Explanation
d-block elements are placed between s- and p-.
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two electrons
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three electrons
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four electrons
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five electrons
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one electron
B
Correct answer
Explanation
Nitrogen has 5 electrons in the valency shell. To attain the configuration of noble gas, one nitrogen atom shares with three electrons with three electrons of the other nitrogen atom. Three paired of electrons constituent of triple bond.
Which set of quantum numbers is not applicable for an electron in atom?
A. n = 1, l = 0, m = 0, s = + 1/2
B. n = 1, l = 1, m = 1, s = + 1/2
C. n = 1, l = 0, m = 0, s = - 1/2
D. n = 2, l = 0, m = 0, s = + 1/2
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Only A
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Only B
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Only C
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Only D
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B and D
B
Correct answer
Explanation
‘n’ and ‘l’ can never have same numerical value, ‘l’ is always less than ‘n’, so it is not applicable for an electron in atom.
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Only A
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Only B
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Only A
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Only D
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None of the above
C
Correct answer
Explanation
Element C (1s2, 2s2, 2p5) is one electron short of stable configuration. So, it readily shares one electron with its other atom. The mutual sharing of one pair of electrons between two atoms of C forms a diatomic molecule.
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valences
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nuclei
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waves
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shells
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bound
A
Correct answer
Explanation
Valence electrons are the electrons in the outer-most shell of the atom.
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Atom
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Mixture
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Compound
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Molecule
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Elements cannot be combined
C
Correct answer
Explanation
Compound is formed by chemical combination of elements.
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Elements combine randomly to form a compound.
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Elements are represented by symbols.
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The atoms of an element are different from atoms of other elements.
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The number of atoms present in a molecule of an element is known as the atomicity of the element.
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A compound can be split into simpler substances or elements.
A
Correct answer
Explanation
No, elements combine in fixed proportion by mass to form a compound.
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Krypton
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Germanium
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Hydrogen
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Lead
A
Correct answer
Explanation
Krypton is the answer as it is a noble gas.
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Fluorine
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Chlorine
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Iodine
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Bromine
C
Correct answer
Explanation
Iodine is a non-metal, which has lustre.
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It cannot be converted into anything simpler.
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Each element consists of only one kind of atom.
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It exists as an individual atom or a molecule.
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Different elements are composed of the same atoms.
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Different elements are composed of the different atoms.
D
Correct answer
Explanation
Different elements are composed of different atoms.
A
Correct answer
Explanation
The correct answer is 6 + 8 + 7 + 2 = 23, because there are two hydrogen atoms therefore 1 × 2 = 2.
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gallium
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boron
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germanium
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silicon
A
Correct answer
Explanation
Mendeleev left some blank spaces in the periodic table for those elements, which were not known at that time. He had predicted that these elements would be discovered later on. He even had predicted the properties of these elements in the light of other elements present in the same group. Mendeleev named these elements by prefixing the Sanskrit word ‘Eka’ to the name of preceding element in the same group, i.e. Eka–boron for scandium, Eka–aluminium for gallium and Eka–silicon for germanium.