Arrange the following elements in order of increasing ionization energy: (a) N (b) Ca (c) Rb (d) Se.

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: Identify the position of each element in the periodic table. Nitrogen (N) is in period 2, group 15; Calcium (Ca) is in period 4, group 2; Rubidium (Rb) is in period 5, group 1; and Selenium (Se) is in period 4, group 16.

Step 3: Apply the periodic trend for ionization energy. As you move from left to right across a period, ionization energy increases. As you move down a group, ionization energy decreases.

Step 4: Compare the elements based on their positions. Since N is to the right of Ca and Se in the same period, it has a higher ionization energy. Rb, being further down in group 1, has the lowest ionization energy.

Step 5: Arrange the elements in order of increasing ionization energy based on the trends: Rb < Ca < Se < N.

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 or ion 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 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 or down the periodic table. For ionization energy, elements on the right side of the table (like nitrogen and selenium) typically have higher ionization energies than those on the left (like calcium and rubidium). Understanding these trends helps in predicting the order of ionization energies among different elements.

Group and Period Position

The position of an element in the periodic table, defined by its group (column) and period (row), significantly affects its ionization energy. Elements in Group 1 (alkali metals) like rubidium have low ionization energies, while nonmetals in Group 15 (like nitrogen) and Group 16 (like selenium) have higher ionization energies. This positioning helps in arranging elements based on their ionization energy.