Structure of Atom MCQ Quiz - Objective Question with Answer for Structure of Atom - Download Free PDF

The correct answer is option 1, i.e Ductility.

• The ability of metals to be drawn into thin wires is called ductility.
• Gold is the most ductile metal.
• A wire of about 2 km length can be drawn from one gram of gold.
• It is because of their malleability and ductility that metals can be given different shapes according to our needs.

Ductility:

• Ductility is the property of the material that enables it to be drawn out or elongated to an appreciable extent before rupture occurs.
• The percentage elongation or percentage reduction in the area before the rupture of a test specimen is the measure of ductility. Normally if the percentage elongation exceeds 15% the material is ductile and if it is less than 5% the material is brittle.
• Lead, copper, aluminium, mild steel are typical ductile materials.

Source: NCERT (Chapter - Metal and Non-Metal) please go through page no. 38

• Ductility- Ability of metals to be drawn into thin wires.
• Sonorous-  Ability of metals to produce sound when beaten hard on its surface.
• Malleability- Ability of metals to be beaten into thin sheets.

The correct answer is Tetra-atomic. Key Points

• Monoatomic Molecules:
  • Definition: Molecules composed of a single, unbonded atom.
  • Examples:
    • Noble gases such as helium (He), neon (Ne), and argon (Ar).
• Diatomic Molecules:
  • Definition: Molecules composed of two atoms, which can be of the same or different elements.
  • Examples:
    • Same element: Hydrogen (H2), oxygen (O2), nitrogen (N2).
    • Different elements: Carbon monoxide (CO).
• Tetra-atomic Molecules:
  • Definition: Molecules composed of four atoms.
  • Examples:
    • Phosphorus (P4).
    • Ammonia (NH3).
    • Sulfur trioxide.

The correct answer is Atomic nucleus.

Key Points

• The discovery of the atomic nucleus was a result of Rutherford's famous alpha-particle scattering experiment conducted in 1911.
• Rutherford observed that a small fraction of alpha particles were deflected at large angles, while most passed through the gold foil, indicating the presence of a dense, positively charged core.
• This dense core was named the nucleus, which contains most of the atom's mass and is positively charged due to the presence of protons.
• The experiment disproved the earlier "plum pudding model" proposed by J.J. Thomson, leading to the development of the nuclear model of the atom.
• This groundbreaking discovery laid the foundation for modern atomic theory and nuclear physics.

Additional Information

• Alpha particles:
  • Alpha particles are helium nuclei consisting of two protons and two neutrons.
  • In Rutherford's experiment, alpha particles were used as projectiles to study atomic structure.
• Gold foil experiment:
  • In this experiment, a thin sheet of gold foil was bombarded with alpha particles.
  • Most particles passed through the foil undeflected, while some were scattered at large angles, leading to the conclusion of a dense nucleus.
• Nuclear model of the atom:
  • Rutherford proposed that an atom consists of a small, dense nucleus surrounded by electrons in empty space.
  • This model replaced the "plum pudding model" and introduced the concept of a central nucleus.
• Limitations of Rutherford's model:
  • While the nuclear model explained the presence of the nucleus, it could not explain the stability of electrons in orbit.
  • This limitation was later addressed by Niels Bohr in his atomic model.
• Impact on modern science:
  • The discovery of the nucleus was pivotal in advancing fields like nuclear physics, quantum mechanics, and chemistry.
  • It also led to the discovery of protons and neutrons as subatomic particles within the nucleus.

The correct answer is Sodium, Na, 1.

Key Points

• The element with atomic number 11 is Sodium (Na), as per the periodic table.
• Sodium is an alkali metal and belongs to Group 1 in the periodic table.
• Sodium has a valency of 1 because it loses one electron to form a stable Na⁺ ion.
• The symbol for Sodium is Na, derived from its Latin name "Natrium."
• It is highly reactive and is commonly found in nature as compounds like sodium chloride (table salt).

Additional Information

• Atomic Number:
  • The atomic number of an element represents the number of protons in its nucleus.
  • For Sodium (Na), the atomic number is 11, meaning it has 11 protons and 11 electrons in its neutral state.
• Electron Configuration of Sodium:
  • The electronic configuration of Sodium is 1s² 2s² 2p⁶ 3s¹.
  • The single electron in the outermost shell (3s) is responsible for its valency of 1.
• Sodium's Reactivity:
  • Sodium is a highly reactive metal, reacting vigorously with water to form sodium hydroxide and hydrogen gas.
  • To prevent unwanted reactions, Sodium is stored in inert substances like oil.
• Role in Biological Systems:
  • Sodium ions (Na⁺) play a crucial role in maintaining fluid balance and nerve signal transmission in the human body.
  • Excess or deficiency of sodium in the body can lead to health issues such as hypernatremia or hyponatremia.
• Common Compounds of Sodium:
  • Sodium forms various compounds like sodium chloride (NaCl), sodium bicarbonate (baking soda), and sodium hydroxide (caustic soda).
  • Sodium chloride is essential for human consumption and is used as a preservative and flavor enhancer in food.

The correct answer is Stability of the atom.

Key Points

• Rutherford's nuclear model proposed that the atom consists of a dense, positively charged nucleus surrounded by electrons in orbits.
• While it accurately described the presence of a nucleus and its positive charge, it failed to explain why electrons, continuously accelerating in circular orbits, do not lose energy and spiral into the nucleus.
• The model could not account for the stability of the atom, as classical electrodynamics predicted that accelerating electrons should emit electromagnetic radiation and lose energy.
• The inability to explain the atom's stability led to the development of Bohr's model, which introduced quantized orbits to resolve this issue.
• Other aspects of the atom, such as the size comparison between the nucleus and the atom or the nucleus being positively charged, were successfully explained by Rutherford's model.

Additional Information

• Rutherford's Gold Foil Experiment:
  • Rutherford directed alpha particles at a thin sheet of gold foil and observed their scattering pattern.
  • Most alpha particles passed through, but some were deflected at large angles, suggesting a dense, positively charged nucleus.
  • This experiment disproved J.J. Thomson's "plum pudding model" of the atom.
• Limitations of Rutherford's Model:
  • It could not explain the stability of atoms as per classical physics.
  • It failed to describe the discrete spectral lines observed in atomic emission spectra.
• Bohr's Model as an Improvement:
  • Bohr introduced the concept of quantized energy levels for electrons, addressing the stability issue.
  • Electrons could only occupy specific orbits without radiating energy.
• Key Terminology:
  • Electromagnetic Radiation: Energy emitted by accelerating charged particles in the form of waves.
  • Quantization: The concept that certain physical properties, like energy, can only take discrete values.

• The word ‘atom’ is coined by Democritus.
• He suggested that if we go on dividing matter at a certain point the atom becomes indivisible or cannot be divided further.
• He called these particles as atoms (Indivisible).

 

Scientist	Discovered
Thomson	Electron
E Rutherford	Discovered alpha and beta particles
John Dalton	Father of Atomic Theory

• Group 1 elements in the Periodic table are known as Alkali metals
• They have ns1 outermost configuration and belong to the S-block Elements.
• They also have a strong tendency to donate their valence electrons in the outermost shell to form strong ionic bonds.
• It contains elements from Lithium (Li) to Francium (Fr).

The correct answer is Phosphorous.

Key Points

• The present number of atoms in any molecule of an element is called its atomicity.
• Tetra atomic elements are those which are made up of four atoms. 
• Phosphorous exists as molecules made up of four atoms in a tetrahedral structure.
• Each phosphorus molecule consists of four atoms of phosphorus.

Important Points

• The following table shows the atomicity of some elements. 

• Electron Shell (also called a Principle energy level) is the region where electrons revolve around the nucleus of an atom.
• The general formula of filling electron in the shell is 2(n²); where n is the number of the shell.

SHELL	n	2(n2)	SHELL MAXIMUM ELECTRON
K	1	= 2(12)	2
L	2	= 2(22)	8
M	3	= 2(32)	18
N	4	= 2(42)	32
O	5	= 2(52)	50

The correct answer is option 1, i.e. Fluorine.

• Fluorine is the most electronegative element.
• As we move right in a period, the electronegativity keeps increasing up to the halogens.
• This is because the number of electrons keeps increasing in the same valence shell so hold of the nucleus on the electrons is tight.
• And as we move down in a group, the electronegativity decreases. This is due to the fact that the number of shells keeps increasing down the group so the hold of the nucleus on the valence electron(s) keeps decreasing.
• Since Flourine is the first member of the halogen family (the rightmost group before noble gases), therefore it is the most electronegative element.

• Newlands Law of Octaves classification attempted to arrange elements by the atomic weight
• According to Newlands Law of Octaves classification, the eighth element starting from the given one kind is a repetition of the first element in the given kind
• This is similar to the property of musical notes
•  The eighth element would have similar atomic weight as that of the first one
• In this way, Thorium was the last element in the Newlands Law of Octaves classification

• Atomic number 56, Barium belongs to s - block elements.
• Electronic configuration for the Barium [Xe]6s²
• Modern Periodic Table is classified into the following elements - p-block, s-block, d-block, and f-block.
• s-block elements include alkali metals and alkaline earth metals.

 

The correct answer is helium.

Key Points

• Alpha Particle
  • α-particles consist of two protons and two neutrons.
  • They are doubly-charged helium ions. Since they have a mass of 4 u, the fast-moving α-particles have considerable energy.
  •  An alpha particle is obtained by removing 2 electrons from a helium atom. So, an alpha particle is a doubly-charged helium ion.
•  Helium:
  • Helium is a chemical element with the symbol He and atomic number 2.
  • It is a colourless, odorless, tasteless, non-toxic, inert, monatomic gas and the first in the noble gas group in the periodic table.
  •  Its boiling and melting point are the lowest among all the elements.
  • It is the second lightest and most abundant element in the observable universe (hydrogen is the lightest and most abundant).

Additional Information

• Lithium
  • ​Lithium is a chemical element with the symbol Li and atomic number 3.
  • It is a soft, silver-white metal belonging to the alkali metal group of chemical elements.
• ​Beryllium
  • Beryllium is very similar to Aluminium.
  • Beryllium is soft and has a low density.
  • It is used in gears and in alloys with copper or nickel.
  • Beryllium is used in Nuclear Reactors.
  • Oxides of Beryllium have a high melting point.
• Hydrogen​
  • Hydrogen was discovered by Henry Cavendish.
  • Hydrogen gas is called as the fuel of the future.
  • Most abundant element in the universe: Hydrogen.
  • Most abundant element on earth's crust: Oxygen
  • Hydrogen is the 'lightest element' in the periodic table.
  • Lithium is the 'lightest metal' in the periodic table.

The correct answer is option 3, i.e. John Dalton.