Question

Arrange the following atoms in order of increasing ionization energy: \(\mathrm{Si}, \mathrm{K}, \mathrm{P},\) and \(\mathrm{Ca}\)

Short answer

Order of increasing ionization energy: K, Ca, Si, P.

Step-by-step solution

Understand Ionization Energy

Ionization energy is the energy required to remove an electron from an atom. Generally, ionization energy increases across a period (from left to right) and decreases down a group on the periodic table.

Identify Periodic Table Positions

Locate the elements Si (Silicon), K (Potassium), P (Phosphorus), and Ca (Calcium) on the periodic table. Silicon and phosphorus are in period 3, while potassium and calcium are in period 4.

Evaluate Period Trends

Within period 3, phosphorus is to the right of silicon, so P has a higher ionization energy than Si. For period 4, the trends suggest that K will have a lower ionization energy than Ca.

Compare Across Periods

Generally, ionization energy increases from left to right across the table and decreases from top to bottom. Thus, Si and P have higher ionization energies than K and Ca, with P being the highest of all and K being the lowest.

Order the Elements

Based on the trends, order the elements from lowest to highest ionization energy: K < Ca < Si < P.

Key concepts

Periodic Table

The periodic table is like a map for understanding the properties of elements, including ionization energy. It helps us predict how elements behave. Generally, elements are arranged by increasing atomic number. The periodic table is organized into rows called periods, and columns called groups or families.

• Periods indicate the number of occupied electron shells.
• Groups indicate elements with similar chemical properties.

The location of an element provides insight into its electron configuration and its tendencies, such as ionization energy. As we move across a period from left to right, atoms gain more protons. This leads to a greater attraction between electrons and the nucleus. Understanding these basics helps predict ionization energy and other properties.

Electron Removal

Ionization energy deals with the energy required to remove an electron from an atom. The process of electron removal is key to understanding chemical reactivity.
Removing an electron requires overcoming the attractive force of the positive nucleus. The amount of energy needed is the ionization energy. Several factors affect this process:

• Distance of the electron from the nucleus: Electrons farther away are easier to remove.
• Nuclear charge: A greater positive charge holds electrons more tightly.
• Shielding effect: Inner electron shells can block the pull on outer electrons.

Succeeding in electron removal and ionization energy understanding, through these factors, is important for predicting the behavior of elements.

Period Trends

Period trends are patterns in the periodic table that help us predict various properties, such as ionization energy. These trends are not arbitrary but reflect underlying principles.
As we move across a period from left to right, ionization energy tends to increase. This happens because:

• Electrons are being added to the same energy level while the nuclear charge increases, pulling electrons closer.
• The increased attraction makes it harder to remove an electron.

Conversely, moving down a group, ionization energy decreases since outer electrons are further from the nucleus and are more shielded by inner electrons. Recognizing these trends allows for predictions about elements' chemical behavior.

Element Comparison

Comparing elements involves examining their positions on the periodic table to predict their properties, like ionization energy. For example, in the exercise, we're looking at silicon (\(\text{Si} \)), potassium (\(\text{K} \)), phosphorus (\(\text{P} \)), and calcium (\(\text{Ca} \)).

• \(\text{K} \) is at the start of period 4 and has a low ionization energy.
• \(\text{Ca} \) follows \(\text{K} \) in period 4, so it has a slightly higher ionization energy.
• \(\text{Si} \) and \(\text{P} \) are in period 3, with \(\text{P} \) to the right of \(\text{Si} \), giving it the highest ionization energy among the four.

Using these comparisons and understanding period trends can help us list the elements in order of increasing ionization energy, accurate to their chemical nature and periodic position.