Question

question 32 (1 point)
which of the following elements has the smallest first ionization energy?
potassium
sodium
magnesium
calcium
question 33 (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
higher
lower
unpredictable
the same
question 34 (1 point)
as you move from left to right across the second period of the periodic table
ionization energy increases.
atomic mass decreases.
electronegativity decreases.
atomic radii increase.

Explanation:

Question 32

Ionization energy is the energy required to remove an electron from an atom. As we move down a group in the periodic table, the first ionization energy decreases because the outermost electrons are further from the nucleus and are less tightly held. Potassium (\(K\)) is in the fourth period, sodium (\(Na\)) in the third, magnesium (\(Mg\)) in the third (but to the right of \(Na\) in the period, so higher ionization energy than \(Na\) as ionization energy increases across a period), and calcium (\(Ca\)) in the fourth (but to the right of \(K\) in the period, so higher ionization energy than \(K\)). Since \(K\) is further down the group compared to \(Na\) (and \(Mg\), \(Ca\) are to the right of \(K\) in their respective periods), \(K\) has the smallest first - ionization energy among the given elements.

Electronegativity is the ability of an atom to attract electrons in a chemical bond. As we move from left to right across a period in the periodic table, the electronegativity increases. This is because the nuclear charge increases (more protons in the nucleus) while the number of electron shells remains the same. So, the elements on the right side of a period have a greater ability to attract electrons compared to those on the left side.

• Ionization energy: As we move from left to right across a period (e.g., the second period), the ionization energy increases. This is because the nuclear charge increases (more protons) and the electrons are in the same shell, so the electrons are more tightly held, and more energy is required to remove an electron.
• Atomic mass: Generally, atomic mass increases from left to right across a period as we have more protons and neutrons in the atoms of elements with higher atomic numbers.
• Electronegativity: Increases from left to right across a period (as explained in Question 33).
• Atomic radii: Decreases from left to right across a period because the increased nuclear charge pulls the electrons closer to the nucleus.

Answer:

a. potassium

Question 33