Explanation

Explanation

• The shielding effect decreases across a period.
• This is because the increasing nuclear charge is not fully counterbalanced by the same number of inner electrons, resulting in a weaker shielding effect.

Explanation

The incorrect statement is "sigma bond is weaker than a pi bond" because a sigma bond is stronger than a pi bond.

Sigma bond: Formed by direct head-on overlap of orbitals, resulting in a strong bond. 

Pi bond: Formed by sideways overlap of p orbitals, resulting in a weaker bond compared to a sigma bond. 

Explanation

The biosphere includes all of these: the Atmosphere, the Hydrosphere, and the Lithosphere.

The biosphere is the zone on Earth where life exists, encompassing the living organisms and their interactions with the surrounding environment, including the atmosphere, hydrosphere (water bodies), and lithosphere (land).

Explanation

Explanation

When the 6d orbital is completely filled, the next electron enters the 7p orbital.

This is based on the Aufbau principle, which dictates that electrons first occupy the lowest energy levels available.

After the 6d orbitals (which can hold up to 10 electrons) are filled.

The 7p orbitals (which can hold up to 6 electrons) become the next lowest energy.

Explanation

Molecular crystals are generally soft and stable.

They are composed of molecules held together by relatively weak intermolecular forces, which results in them being easily deformed and having low melting points.

While they are generally stable under normal conditions, they can become unstable under extreme temperatures or pressures.

Explanation

Vacuum distillation is used to distill substances at lower temperatures by reducing the pressure, which lowers the boiling point of the substances.

Explanation

The iodoform test is a chemical reaction used to identify the presence of a methyl ketone group (CH3-CO-) in a compound.

When a methyl ketone reacts with iodine and sodium hydroxide, it produces a yellow precipitate of iodoform.

This makes the iodoform test a reliable way to detect methyl ketones.

Explanation

When an alcohol reacts with an alkyl magnesium halide (Grignard reagent), the product is an alkane.

The Grignard reagent acts as a strong base, removing the acidic hydrogen from the alcohol's hydroxyl group (-OH) and forming a new carbon-hydrogen (C-H) bond, thus creating an alkane.

The other product is a magnesium alkoxide salt.