Question

1. what is the atomic number of the atom in figure 2.2: a. 2 b. 3 c. 4 d. 6 e. 12 14. when a pair of electrons is shared equally between two atoms, the bond formed is called a(n): a. ionic bond b. hydrogen bond c. carbon bond d. polar covalent bond e. nonpolar covalent bond 15. in the chemical reaction, hcl + naoh → h₂o + nacl, the chemical naoh is considered to be a. water b. base c. product d. acid e. salt 16. hydrogen bonding between water molecules is responsible for: a. polarity b. denaturation of proteins c. enzyme structure d. nonpolar covalent bonding e. surface tension

Explanation:

Step1: Recall atomic number definition

The atomic number is the number of protons in an atom's nucleus.

Step2: Identify number of protons in the figure

The figure shows 6 protons ($p^{+}$) in the nucleus.

Step1: Recall bond - type definitions

An ionic bond is formed by the transfer of electrons, a hydrogen bond is a weak attraction between polar molecules, a carbon - bond is a general term for bonds involving carbon, a polar covalent bond is when electrons are shared unequally, and a nonpolar covalent bond is when electrons are shared equally.

Step2: Match with given description

Since electrons are shared equally, it is a nonpolar covalent bond.

Step1: Recall acid - base reaction concepts

In the reaction $HCl + NaOH
ightarrow H_2O+NaCl$, $HCl$ is an acid and $NaOH$ is a base. A base is a substance that can accept a proton ($H^{+}$) or release hydroxide ions ($OH^{-}$) in solution.

Step2: Identify the role of $NaOH$

$NaOH$ is a base as it dissociates to release $OH^{-}$ ions.

Step1: Recall properties related to hydrogen - bonding in water

Hydrogen bonding between water molecules gives water unique properties. Polarity is due to the uneven distribution of electrons in a water molecule, denaturation of proteins is mainly related to changes in temperature, pH etc., enzyme structure is related to amino - acid sequences and folding, nonpolar covalent bonding is not related to hydrogen bonding in water.

Step2: Identify the property due to hydrogen - bonding

Hydrogen bonding between water molecules is responsible for surface tension, as it causes water molecules at the surface to be pulled together.

Answer:

d. 6