Question

For the following categories of elements, state the possible number(s) of electrons in their outermost orbitals in the ground state? (Chapter 5) a. \(\mathrm{p}\) -block elements b. nitrogen-group elements c. d-block elements d. noble-gas elements e. s-block elements

Short answer

In summary, for each category of elements in their ground state, the number of electrons in their outermost orbitals is as follows: a. p-block elements: 1, 2, 3, 4, 5, or 6 electrons b. nitrogen-group elements: 5 electrons c. d-block elements: 1 to 12 electrons d. noble-gas elements: 2 electrons (Helium) and 8 electrons (others) e. s-block elements: 1 electron (alkali metals) and 2 electrons (alkaline earth metals)

Step-by-step solution

p-block elements

p-block elements are found in groups 13 to 18 of the periodic table, so they have 1 to 6 valence electrons in their outermost orbitals. Their general electronic configuration is ns^2 np^(1-6) for n ≥ 2. There are 6 possible values for the number of electrons in the outermost orbital: 1, 2, 3, 4, 5, or 6. 2.

nitrogen-group elements

Nitrogen-group elements are found in Group 15 of the periodic table. They have 5 valence electrons in their outermost orbitals. Their general electronic configuration is ns^2 np^3, where n ≥ 2. Thus, nitrogen-group elements have 5 electrons in their outermost orbitals. 3.

d-block elements

d-block elements are the transition metals found in groups 3-12 in the periodic table. The number of valence electrons in d-block elements can be variable as they involve the filling of (n-1)d orbitals in addition to ns orbitals. Their general electronic configuration is (n-1)d^(1-10) ns^(0-2), where n ≥ 4. They can have 1 to 12 valence electrons. 4.

noble-gas elements

Noble-gas elements are found in Group 18 of the periodic table. These elements have a completely filled outermost shell, except for helium. The general electronic configuration for helium is 1s^2, and for the others, it is ns^2 np^6, where n ≥ 2. Helium has 2 electrons and all other noble gases have 8 electrons in their outermost orbitals. 5.

s-block elements

s-block elements consist of alkali metals and alkaline earth metals. They are found in groups 1 and 2 of the Periodic Table. Alkali metals have 1 valence electron in their s-orbital, while alkaline earth metals have 2 valence electrons in their s-orbital. Their general electronic configuration is ns^(1-2), with n ≥ 2 for alkali metals and n ≥ 3 for alkaline earth metals. The possible number of electrons in the outermost orbitals for s-block elements is 1 or 2.

Key concepts

Electron Configuration

Understanding the arrangement of electrons within an atom is pivotal for comprehending various chemical properties. This arrangement is known as the electron configuration.

Electrons reside in different energy levels or shells around the nucleus, and these shells are further divided into subshells designated as s, p, d, and f. The particular distribution of electrons among these subshells dictates the electron configuration of an element. For example, the s subshell can hold a maximum of 2 electrons, while the p subshell can accommodate up to 6 electrons.

Knowing the electron configuration is important not just for predicting the reactivity of elements, but also for understanding their placement in the periodic table. The 'ns^2 np^6' notation, for instance, indicates an arrangement where the outermost s subshell contains 2 electrons and the outermost p subshell is fully occupied with 6 electrons, which is characteristic of noble gases.

Periodic Table

The periodic table is not just a chart of elements; it's a powerful tool for predicting the types of chemical reactions that can occur. Each of the 118 known elements occupies a unique position based on its atomic number—the number of protons in the nucleus.

Elements in the same column, or group, tend to have similar properties because they share the same number of valence electrons. These shared characteristics make it easier to comprehend patterns of reactivity across different elements. Furthermore, the periodic table divides into several blocks, namely s, p, d, and f, which reflect the type of orbital that is being filled with electrons in that section of elements.

P-Block Elements

P-block elements are located on the right-hand side of the periodic table and encompass groups 13 through 18. These elements have their last electrons entering the p orbitals, which can hold a maximum of six electrons.

Characteristic Properties

These elements can showcase up to six valence electrons as observed in their general electron configuration, ns^2 np^(1-6). This diversity in electron numbers allows p-block elements to participate in a myriad of chemical reactions, forming covalent bonds with various electron configurations. The p-block includes metals, nonmetals, and metalloids, indicating its vast array of chemical and physical properties.

D-Block Elements

Found at the central section of the periodic table, d-block elements—or transition metals—are known for their metallic characteristics and complex electron arrangements.

Unlike the s and p blocks, these elements have a (n-1)d orbital involvement, which means their outer electron shell isn't the only one that's active. The electron configuration typical for these elements ranges from (n-1)d^(1-10) ns^(0-2). It's these peculiar configurations that grant transition metals their unique properties, such as multiple oxidation states, and abilities to form colored compounds and act as good conductors of heat and electricity.

S-Block Elements

The s-block elements include alkali and alkaline earth metals, found in groups 1 and 2 of the periodic table. Their defining feature is having the s orbital filled with electrons in their outer shells.

Alkali metals possess a single electron in their outermost s-orbital (ns^1), whereas alkaline earth metals have two (ns^2). These configurations lead to high reactivity, especially for alkali metals which readily lose their single valence electron. These elements play crucial roles in various biological processes and industrial applications. For instance, the alkali metal sodium is integral to nerve impulse transmission, while magnesium, an alkaline earth metal, is a key component in chlorophyll.