Which element in each of the following pairs has the higher ionization energy? (a) As or Cl (b) Mg or Ba

Verified step by step guidance

Step 1: Understand the concept of ionization energy. Ionization energy is the energy required to remove an electron from an atom in its gaseous state. It generally increases across a period and decreases down a group in the periodic table.

Step 2: Analyze the position of As and Cl in the periodic table. Arsenic (As) is in group 15 and period 4, while Chlorine (Cl) is in group 17 and period 3.

Step 3: Apply the periodic trend for ionization energy to As and Cl. Since Cl is to the right of As in the same period, Cl has a higher ionization energy than As.

Step 4: Analyze the position of Mg and Ba in the periodic table. Magnesium (Mg) is in group 2 and period 3, while Barium (Ba) is in group 2 and period 6.

Step 5: Apply the periodic trend for ionization energy to Mg and Ba. Since Mg is above Ba in the same group, Mg has a higher ionization energy than Ba.

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Ionization Energy

Ionization energy is the energy required to remove an electron from an atom in its gaseous state. It is a key factor in determining an element's reactivity and is influenced by the atomic size and the effective nuclear charge. Generally, ionization energy increases across a period from left to right and decreases down a group in the periodic table.

Periodic Trends

Periodic trends refer to the predictable patterns observed in the properties of elements as you move across periods or down groups in the periodic table. For ionization energy, elements on the right side of the table (like Cl) typically have higher ionization energies than those on the left (like As), while elements higher up in a group (like Mg) have higher ionization energies than those lower down (like Ba).

Effective Nuclear Charge

Effective nuclear charge (Z_eff) is the net positive charge experienced by an electron in a multi-electron atom. It accounts for the shielding effect of inner electrons that reduces the full nuclear charge. A higher effective nuclear charge leads to a stronger attraction between the nucleus and the outer electrons, resulting in higher ionization energy, particularly for elements with fewer electron shells.

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Related Practice

Textbook Question

In the following pictures of oxides, red spheres represent O atoms or ions, and green spheres represent atoms or ions of a second- or third-row element in its highest oxidation state.

(1)

(2)

(3)

(b) Identify each oxide as ionic or covalent.

Textbook Question

Look at the location of elements A, B, C, and D in the following periodic table:

(a) Write the formula of the oxide that has each of these elements in its highest oxidation state.

Textbook Question

The following models represent the structures of binary

oxides of second- and third-row elements in their highest

oxidation states:

(a) Identify the non-oxygen atom in each case, and write the molecular formula for each oxide.