Explanation

VSEPR theory is used to predict the 3-D molecular geometry or shape of molecules by considering the repulsion

Between electron pairs in the valence shell of an atom,

Which arrange themselves to minimize this repulsion. 

Explanation

The bond angle in a water molecule is approximately 104.5 degrees.

This angle is smaller than the ideal tetrahedral angle of 109.5 degrees

Because the two lone pairs of electrons on the oxygen atom exert more repulsion

Than the bonded hydrogen atoms, pushing the O-H bonds closer together. 

Explanation

Explanation

The metallic and non-metallic character of p-block elements varies as follows:

Along the period the metallic character decreases, whereas the non-metallic character increases.

It is because on moving across the period, the atomic size decreases due to the increased nuclear charge, and hence, ionization energy increases.

Explanation

• Atomic radius decreases along a period as you move from left to right.
• This is because the number of protons in the nucleus increases, which pulls the electrons closer to the nucleus, resulting in a smaller atomic radius.

Explanation

Explanation

The value of Planck's constant is 6.63 × 10⁻³⁴ Js.

This constant is fundamental in quantum mechanics.

It relating the energy of a photon to its frequency.

Explanation

Explanation

One mole of any substance contains Avogadro's number of particles.  

So, 1 mole of NaCl contains 6.022 × 10²³ formula units.

Explanation

• An atom typically has an equal number of electrons and protons.
• They are equal in number to the atomic number (Z) of the element.
• This number is unique to each element and determines the properties of the element.