Which one among the following is correct regarding ²⁰Ne, ²³Na⁺, ¹⁹F^- and ²⁴Mg²⁺?

• They are isomers of each other

• They are isotopes of each other

• They are isoelectronic with each other

• All of the above

Which of the following pairs is/are correctly matched?

1. Isotopes: Atoms with the same atomic number but a different atomic mass
2. Isobars: Atoms with the same number of neutrons but different atomic number
3. Isotones: Atoms with same mass number but different atomic number

Select the correct answer using the code given below:

• 1, 2 and 3

• 1 only

• 1 and 2 only

• 2 only

Sometimes, indigestion is caused by the secretion of too much hydrochloric acid in the stomach. To ease the pain caused, a tablet can be taken that reacts to reduce the amount of acid present. Which one among the following would be inappropriate for a manufacturer to include as a major reactant in the tablet?

• CaCO₃

• MgCO₃

• NaOH

• Mg(OH)₂

The nucleus of a singly ionized carbon atom contains

• 6 protons and 6 neutrons

• 5 protons and 6 neutrons

• 6 protons, 6 neutrons and 6 electrons

• 12 protons, 6 neutrons and 6 electrons

The following equation is an example of a redox reaction, in which Cl₂ is the oxidizing agent and FeBr₃ is the reducing agent:

2FeBr₃(aq) + 3Cl₂ (g) = 2FeCl₃(aq) + 3Br₂(1)

Which one among the following statements is incorrect for this redox reaction?

• Oxidizing agents are themselves reduced

• Reducing agents gain or appear to gain electrons

• Reducing agents are themselves oxidized

• Oxidizing agents oxidize other substances.

206.

Which one among the following nitrogen compounds has the least percentage of nitrogen by mass?

• (NH₄)₃PO₄

• NH₃

• NH₄OH

• NH₄NO₃

Which one among the following is the correct order of the amount of lime (CaO), silica (SiO₂), alumina (Al₂O₃), and ferric oxide (Fe₂O₃) in Portland cement?

• CaO > SiO₂ > Al₂O₃ > Fe₂O₃

• SiO₂ > CaO > Fe₂O₃ > Al₂O₃

• Al₂O₃ > SiO₂ > CaO > Fe₂O₃

•  Fe₂O₃ > Al₂O₃ > SiO₂ > CaO

Which one among the following transitions of electron of hydrogen atom emits radiation of the shortest wavelength?

• n = 2 to n = 1

• n = 3 to n = 2

• n = 4 to n = 3

• n = 5 to n = 4

Which one among the following is the most appropriate statement with respect to the atomic weight of an element?

• The atomic weight of an element is the sum total of the number of protons and neutrons present in the atom of the element

• Unlike mass number, the atomic weight of an element can be a fraction

• The atomic weight of an element is a whole number

• The atomic weight of all the atoms in an element is the same

Which one among the following is the major constituent of soda-lime glass?

• Sodium oxide

• Calcium oxide

• Calcium carbonate

• Silica