Question

Write the symbol and the abbreviated electron configuration of the element described. (a) the metal in Group 1 whose atom is the smallest (b) the alkaline earth metal with the heaviest atom (c) the transition metal in period 4 whose atom contains the fewest protons (d) the largest metalloid atom with the maximum number of unpaired p electrons (e) an element in period 4 whose \(+2\) ion is isoelectronic with argon

Short answer

Question: Identify the following elements and their abbreviated electron configurations based on the descriptions provided: a) Group 1 metal with the smallest atom b) Alkaline earth metal with the heaviest atom c) Period 4 transition metal with fewest protons d) Largest metalloid atom with the maximum number of unpaired p electrons e) Period 4 element with a \(+2\) ion isoelectronic with argon Answer: a) Hydrogen (H) with an electron configuration of \(1s^1\) b) Radium (Ra) with an electron configuration of \([Rn]7s^2\) c) Scandium (Sc) with an electron configuration of \([Ar]3d^14s^2\) d) Antimony (Sb) with an electron configuration of \([Kr]4d^105s^25p^3\) e) Calcium (Ca) with an electron configuration of \([Ar]4s^2\)

Step-by-step solution

a) Group 1 metal with the smallest atom

According to the periodic table, the Group 1 metal with the smallest atom is hydrogen (H). This is because the size of an atom decreases as you go across a period and increases as you go down a group. Therefore, hydrogen (being the first element) is the smallest Group 1 metal. The atomic number of hydrogen is 1, which means it has one electron. The abbreviated electron configuration for hydrogen is \(1s^1\).

b) Alkaline earth metal with the heaviest atom

To find the alkaline earth metal with the heaviest atom, we need to look at the bottom of Group 2 in the periodic table, as the mass of an atom increases as you go down a group. The last element in Group 2 is radium (Ra). Its atomic number is 88, and its abbreviated electron configuration is \([Rn]7s^2\).

c) Period 4 transition metal with fewest protons

The transition metals are located in the middle of the periodic table, occupying the d-block. To find the transition metal in period 4 with the fewest protons, we will identify the first transition metal in period 4 (top-left corner of the d-block in that period). That element is scandium (Sc), with an atomic number of 21. Its abbreviated electron configuration is \([Ar]3d^14s^2\).

d) Largest metalloid atom with the maximum number of unpaired p electrons

Metalloids are elements found along the staircase dividing line between metals and non-metals. When talking about the largest metalloid atom, we need to look at the bottom-right corner of the metalloid section. To maximize the number of unpaired p electrons, we must find the element that has the largest number of electrons in the p orbitals but are not yet full. That element is antimony (Sb). Its atomic number is 51, and its abbreviated electron configuration is \([Kr]4d^105s^25p^3\).

e) Period 4 element with a \(+2\) ion isoelectronic with argon

Isoelectronic ions have the same number of electrons. Argon (Ar) has an atomic number of 18, so it has 18 electrons. A Period 4 element with a \(+2\) ion means that it has lost two electrons through ionization. Since the ion has to be isoelectronic with argon, that means the original element must have 20 electrons in total (18 from the ion and 2 as lost to reach \(+2\) state). The element with an atomic number of 20 is calcium (Ca), which is also in Period 4. The abbreviated electron configuration of calcium is \([Ar]4s^2\). The calcium \(+2\) ion loses the two 4s electrons, leaving it with an electron configuration identical to that of argon, hence being isoelectronic.

Key concepts

Periodic Table

The periodic table is a systematic arrangement of elements, organized by increasing atomic number. It provides a wealth of information at a glance, such as the grouping of elements into metals, non-metals, and metalloids. Additionally, elements are organized into groups (columns) and periods (rows), which signify their chemical properties and reactivities.
The vertical columns, known as groups, share similar chemical behaviors. For instance, Group 1 contains alkali metals like lithium and sodium, which are highly reactive and form similar ionic compounds. On the other hand, periods represent elements with the same number of electron shells but varying valence electrons.
The periodic table also includes distinct sections such as the d-block, which houses the transition metals. This layout allows scientists to quickly deduce an element's potential interactions and its electronic arrangement based solely on its position on the table.

Atomic Structure

Every atom is composed of a nucleus containing protons and neutrons, surrounded by a cloud of electrons. The electrons are arranged in areas called orbitals, which are regions where an electron is most likely found. These orbitals are divided into different energy levels denoted by principal quantum numbers.
Atoms aim for a stable structure, often resembling that of a noble gas configuration with a full outer electron shell. This stable configuration influences how atoms bond and interact with each other.

• Protons, found in the nucleus, carry a positive charge and define the element's identity by its atomic number.
• Neutrons, also in the nucleus, are neutral and contribute to the atomic mass.
• Electrons orbit the nucleus in energy levels, with the valence electrons playing a key role in chemical bonding.

This structural arrangement accounts for the diversity of chemical reactions and bonding patterns seen across the periodic table.

Electron Configuration

Electron configuration describes the arrangement of electrons in an atom, which determines how the atom will interact chemically with other elements. It's expressed using the principal quantum numbers and the letters s, p, d, and f to denote different types of orbitals.
An abbreviated electron configuration utilizes the previous noble gas configuration to simplify the notation. For example, calcium's abbreviated configuration is \([Ar]4s^2\), indicating it has the same electron configuration as argon up to its outer 4s electrons.
Knowing an element's electron configuration can reveal a lot about its chemical reactivity and bonding potential. For example, elements in the same group often have similar configurations in their outer shells, explaining shared chemical properties.

• The s orbital can hold a maximum of 2 electrons.
• The p orbital can hold up to 6 electrons.
• The d orbital accommodates up to 10 electrons.

Understanding electron configurations illuminates the behavior of elements during reactions.

Transition Metals

Positioned in the d-block of the periodic table, transition metals are characterized by their ability to form various oxidation states. This versatility arises from the involvement of d-electrons in bonding.
Transition metals often serve as catalysts and are known for forming colorful compounds due to d-d electron transitions. Their electron configurations typically involve filling d subshells, as seen with scandium, which has the configuration \([Ar]3d^14s^2\).
The properties of transition metals are largely influenced by their electron configurations, leading to traits such as high melting points, conductivity, and mechanical strength.

• Transition metals have d orbitals that can participate in metallic bonding.
• They often form complex ions with interesting geometry.
• These metals can exhibit magnetic properties due to unpaired d electrons.

The flexibility and unique characteristics of transition metals make them essential in both industrial and biological processes.