Problem 100 - Chemistry The Molecular Science

Question

Give the symbol of all the ground-state atoms that have (a) no \(p\) electrons. (b) from two to four \(d\) electrons. (c) from two to four \(s\) electrons.

Step-by-Step Solution

Answer

(a) H, He, Li, Be; (b) Ti, V, Cr; (c) He, Be, Mg, Ca.

Step 1: Identify Atoms with No p Electrons

To find atoms with no p electrons, we consider elements in the periodic table that fill only the s and possibly d orbitals in their ground state. These elements are in the first two columns: the alkali metals and alkaline earth metals. Specific examples include hydrogen (H), helium (He), lithium (Li), beryllium (Be), and sodium (Na).

Step 2: Identify Atoms with Two to Four d Electrons

To find elements with 2-4 d electrons, we look at the transition metals where the d orbitals are being filled. These are found in the d block of the periodic table. Examples of such atoms include titanium (Ti) which has 2 d electrons, vanadium (V) with 3, and chromium (Cr) with 4 d electrons.

Step 3: Identify Atoms with Two to Four s Electrons

Atoms with 2 to 4 s electrons typically include elements with electronic configurations that have 2-4 electrons in the outermost s orbital. These electrons are found in some elements at the beginning of a row or in isolation. Examples include helium (He) with 2 s electrons, beryllium (Be) with 2, magnesium (Mg) with 2, and calcium (Ca) with 2, but only calcium and barium (Ba) typically have 4 s electrons in excited states due to hyper-excited states in higher periods.

Key Concepts

Ground-State Atoms

Ground-state atoms are atoms in their lowest energy state. In this state, electrons are arranged in the lowest available energy levels or orbitals. Each atom has a unique electronic configuration, providing a blueprint of electron arrangement around the nucleus. The configuration follows the Aufbau principle, Hund's rule, and the Pauli exclusion principle.

• Aufbau Principle: Electrons fill orbitals starting from the lowest energy level upwards.
• Hund’s Rule: Every orbital in a subshell is singly occupied before any orbital is doubly occupied.
• Pauli Exclusion Principle: No two electrons in an atom can have the same four quantum numbers.

Ground-state configurations help predict chemical properties and reactivity by showing how atoms will interact or form bonds. For example, elements like hydrogen (H), helium (He), lithium (Li), and others mentioned in the solution have no p electrons. This is because they belong to groups where only s and possibly d orbitals are filled.

Transition Metals

Transition metals are intriguing elements found in the d-block of the periodic table. They are unique due to their ability to form multiple oxidation states. This property arises because electrons from both the s and d orbitals can be used in bonding.

• d-Electrons: The transition metals showcase the filling of their d orbitals as opposed to just the outermost s orbitals found in other metals.
• Elements like titanium (Ti), vanadium (V), and chromium (Cr) represent cases where there are 2 to 4 d electrons.
• These atoms generally exhibit high melting and boiling points and form colored compounds.

Their partially filled d electrons not only contribute to catalytic properties but also to the capacity of these metallic elements to form complex ions. Such typical characteristic behaviors make transition metals versatile and valuable in industrial applications.

Periodic Table

The periodic table is a carefully designed map of the chemical elements. Each column, known as a group, and each row, known as a period, provides a systematic organization that underscores both the atomic structure and chemical characteristics of elements.

• Groups: Elements in the same group have similar properties due to the same number of electrons in their outer shell.
• Periods: Moving across a period sees a gradual change in properties. For instance, elements start as metals and move to nonmetals by the period's end.
• Element Blocks: Different segments or "blocks" (s, p, d, f) in the table indicate the type of subshell being filled with electrons for ground-state configurations.

Elements like alkali metals and alkaline earth metals with no p electrons are found in the s-block, while transition metals with their filling d electrons are in the d-block. Understanding the periodic table structure is essential for predicting electronic configurations and the corresponding chemical properties of different elements.