Chemical Bonding — Set 4
Chemistry · रासायनिक बंधन · Questions 31–40 of 40
The measure of an atom's ability to attract shared electrons is called?
Correct Answer: A. Electronegativity
Electronegativity is a chemical property that describes the tendency of an atom to attract a shared pair of electrons. It increases across a period and decreases down a group in the periodic table. This concept was popularized by Linus Pauling.
Which molecule is a well-known exception to the octet rule with more than 8 electrons?
Correct Answer: C. PCl5
Phosphorus pentachloride (PCl5) is an example of an expanded octet. The central phosphorus atom is surrounded by ten electrons in its valence shell. This is possible for elements in the third period and beyond due to available d-orbitals.
What type of bonding is present in solid Iodine?
Correct Answer: D. Covalent and Van der Waals
In solid Iodine, the atoms within a molecule are covalently bonded. The individual molecules are then held together in a crystal by weak Van der Waals forces. This explains why Iodine sublimes easily when heated.
Which hybridisation is present in the carbon atoms of diamond?
Correct Answer: C. sp3
Each carbon atom in diamond undergoes sp3 hybridisation. This results in four single bonds arranged in a rigid tetrahedral shape. This specific arrangement is why diamond is so hard and has a high refractive index.
What type of bond is formed when p-orbitals overlap sideways?
Correct Answer: D. Pi bond
A pi bond is formed by the lateral or sideways overlap of atomic orbitals. It is generally weaker than a sigma bond because the overlap is less effective. Double and triple bonds consist of one sigma bond and one or two pi bonds.
Which of the following ions has a noble gas configuration?
Correct Answer: C. Mg2+
The magnesium ion (Mg2+) has 10 electrons, which is the same as the noble gas Neon. By losing two electrons, magnesium achieves a stable full outer shell. Most main-group metals form ions with noble gas configurations.
The energy required to separate one mole of an ionic compound into gaseous ions is?
Correct Answer: B. Lattice energy
Lattice energy is a measure of the strength of the forces holding an ionic solid together. Higher lattice energy usually results in higher melting points for the compound. It depends on the charge and size of the ions involved.
Which molecule contains only single covalent bonds?
Correct Answer: B. Ethane
Ethane (C2H6) contains only single covalent bonds between carbon and hydrogen atoms. All the carbon-carbon and carbon-hydrogen bonds in alkanes are sigma bonds. Saturated hydrocarbons are characterized by these single bonds.
Which property of metals is explained by the mobility of valence electrons?
Correct Answer: B. Lustre and conductivity
The shiny appearance (lustre) and electrical conductivity of metals are due to free electrons. These electrons can move easily through the lattice to carry charge or reflect light. This mobility also helps in the rapid transfer of heat.
A covalent bond is formed by?
Correct Answer: A. Sharing of electrons
A covalent bond is formed when two atoms share one or more pairs of electrons. This typically occurs between non-metal atoms. Single, double, and triple bonds involve sharing of 1, 2, and 3 electron pairs respectively.