Question

question 45 (1 point)
compared with the electronegativities of the elements on the left side of a period, the electronegativities of the elements on the right side of the same period tend to be
o a lower
o b higher
o c unpredictable
o d the same

question 46 (1 point)
which of the following decreases with increasing atomic number in group 2a?
o a shielding effect
o b ionic size
o c number of electrons
o d ionization energy

question 47 (1 point)
which of the following statements correctly compares the relative size of an ion to its neutral atom?
o a the radius of an anion is greater than the radius of its neutral atom
o b the radius of a cation is identical to the radius of its neutral atom
o c the radius of a cation is greater than the radius of its neutral atom
o d the radius of an anion is identical to the radius of its neutral atom

Explanation:

Question 45

Electronegativity increases across a period from left to right. This is because as we move from left to right in a period, the atomic number increases, the number of protons in the nucleus increases, and the electrons are added to the same shell. The increased nuclear charge attracts the bonding electrons more strongly, so elements on the right side of a period have higher electronegativities.

• Shielding effect (a): Increases with increasing atomic number in a group as more electron shells are added.
• Ionic size (b): Increases with increasing atomic number in a group as more electron shells are added.
• Number of electrons (c): Increases with increasing atomic number (since atomic number = number of protons = number of electrons in neutral atom, and for group 2A elements, they form +2 ions, but the number of electrons in the ion also increases with atomic number).
• Ionization energy (d): Decreases with increasing atomic number in a group. As atomic size increases (more electron shells), the outermost electrons are farther from the nucleus and are easier to remove.

• An anion is formed by adding electrons to a neutral atom. The added electrons increase electron - electron repulsion, and the electron cloud expands. So, the radius of an anion is greater than the radius of its neutral atom.
• A cation is formed by removing electrons from a neutral atom. Removing electrons reduces electron - electron repulsion, and the remaining electrons are pulled closer to the nucleus. So, the radius of a cation is smaller than the radius of its neutral atom.

Answer:

B. higher

Question 46