Which one is it? Please help

Answer: The correct answer is within the glass, adhesive forces dominate, and on top of the glass, cohesive forces dominate.

Explanation:

Adhesive forces are defined as the molecular forces which are present between different substances. For Example: When water is poured into glass, the molecular forces between the walls of container and water molecules.

Cohesive forces are defined as the molecular forces which are present between same substances.

When water is put in the glass, two types of meniscus form, one is concave meniscus and another is convex meniscus.

Concave meniscus is formed due to adhesive forces and is dominating inside the glass.

Convex meniscus is formed due to cohesive forces and is dominating on the top of glass. As, on the top of glass no walls of glass are present. So, water molecules stick together to other water molecules.

Hence, the correct answer is within the glass, adhesive forces dominate, and on top of the glass, cohesive forces dominate.

Answer:

b. Halogens

Explanation:

Chemical reactions are associated with the 'breaking' of old bonds and formation of new bonds. Since valence electrons are the ones that participate bonding, therefore the reactivity of elements must depend on the ease with which these electrons can be lost or gained.

Noble gases have fully filled (n²np⁶) valence electron configuration and are highly stable and inert.

Carbon family have less that half filled p-orbitals (ns²np²) in their valence configuration and are not very reactive. Metalloids have their reactivity in between metals and non-metals.

Halogens in contrast have a valence electron configuration of ns²np⁵. They only need one more electron to complete their octet and become stable. As a result they are highly reactive i.e. they readily attract electrons and form new bonds.

Answer:

• The correct option is B. The nonpolar substance has a lower boiling point than the polar substance.

Explanation:

• Substances with hydrogen bonding, an intermolecular force, will have much higher  boiling points than those that have ordinary dipole-dipole intramolecular forces. Non-polar molecules have lower boiling points, because they are held together by the weak van der Waals forces.

Note

• However, if size of non polar increases, then its boiling point increases due to increases in van der walls forces with large size.

Answer:

Copper

Explanation: