Question

For each of the following atomic numbers, use the periodic table to write the formula (including the charge) for the simple ion that the element is most likely to form in ionic compounds. a. 13 b. 34 c. 56 d. \(\underline{7}\) e. 87 f. 35

Short answer

The simple ions and their charges for elements with atomic numbers 13, 34, 56, \(\underline{7}\), 87, and 35 are: a. Aluminum: \(Al^{3+}\) b. Selenium: \(Se^{2-}\) c. Barium: \(Ba^{2+}\) d. Nitrogen: \(N^{3-}\) e. Francium: \(Fr^{+}\) f. Bromine: \(Br^{-}\)

Step-by-step solution

Identifying the element corresponding to each atomic number

Use the periodic table to find the elements corresponding to the atomic numbers. Here are the elements corresponding to the given atomic numbers: a. 13: Aluminum (Al) b. 34: Selenium (Se) c. 56: Barium (Ba) d. \(\underline{7}\): Nitrogen (N) e. 87: Francium (Fr) f. 35: Bromine (Br)

Determine the charge of the ion for each element

Using the periodic table, we can make predictions about the charge of the ion that each element is most likely to form. Elements in Groups 1, 2, and 13 tend to lose electrons, whereas elements in Groups 15, 16, and 17 tend to gain electrons. The charges of the simple ions usually correspond to the number of electrons gained or lost to achieve a stable noble gas configuration (a full outer electron shell). a. Aluminum (Al) is in Group 13, so it is likely to lose 3 electrons and form a +3 ion: Al^{3+} b. Selenium (Se) is in Group 16, so it is likely to gain 2 electrons and form a -2 ion: Se^{2-} c. Barium (Ba) is in Group 2, so it is likely to lose 2 electrons and form a +2 ion: Ba^{2+} d. Nitrogen (N) is in Group 15, so it is likely to gain 3 electrons and form a -3 ion: N^{3-} e. Francium (Fr) is in Group 1, so it is likely to lose 1 electron and form a +1 ion: Fr^{+} f. Bromine (Br) is in Group 17, so it is likely to gain 1 electron and form a -1 ion: Br^{-}

Write the formula for each simple ion

Now that we have determined the charge for each ion, we can write the formula for the simple ion of each element. a. Aluminum: Al^{3+} b. Selenium: Se^{2-} c. Barium: Ba^{2+} d. Nitrogen: N^{3-} e. Francium: Fr^{+} f. Bromine: Br^{-}

Key concepts

Atomic Number

The atomic number of an element is fundamental to its identity. It corresponds to the number of protons in the nucleus of an atom. This is what defines the type of element. For example, if an atomic number is 13, the element is aluminum (Al). Similarly, atomic numbers 34, 56, and others represent specific elements: selenium (Se), barium (Ba), and more. Each atomic number is unique to one element.

In the periodic table, elements are arranged in order of increasing atomic number. This arrangement not only helps in identifying an element but also offers insights into their properties. Knowing the atomic number allows us to determine the position of an element in the table, deduce its characteristics, and predict its chemical behavior.

When identifying ions, the atomic number plays a crucial role. It helps determine how an element might lose or gain electrons to form ions, striving toward a stable electron configuration like that of a noble gas.

Ionic Compounds

Ionic compounds are formed through the transfer of electrons between atoms, leading to the creation of ions. These ions are atoms or molecules that have gained or lost electrons, giving them a net charge. The resulting ionic bond arises from the strong electrostatic attraction between oppositely charged ions.

In ionic compounds, metals tend to lose electrons and form positive ions (cations), while non-metals tend to gain electrons and form negative ions (anions). For example, aluminum (Al) can lose three electrons to form a cation (Al^{3+}), while bromine (Br) can gain an electron to form an anion (Br^{-}).

The formula of ionic compounds is determined by balancing the total positive and negative charges so that the compound is electrically neutral. This leads to compounds like sodium chloride (NaCl), magnesium oxide (MgO) and more, where the number of positive and negative charges balance each other out.

Ion Charge

The charge of an ion depends on the gain or loss of electrons. Elements aim to have a stable electron configuration, often that of the nearest noble gas. Metals usually lose electrons, resulting in a positive charge, while non-metals gain electrons, acquiring a negative charge.

For example, aluminum, in group 13, loses three electrons to achieve a stable configuration, forming a +3 ion ( Al^{3+}). On the other hand, elements like bromine in group 17 gain one electron, forming a -1 ion ( Br^{-}).

Understanding ion charge helps predict how elements combine to form compounds. Charges must balance to form stable ionic compounds. This concept is central to predicting and writing chemical formulas for compounds.

Group Numbers

Group numbers on the periodic table provide valuable information about the elements and their chemical behaviors. Each group, usually a vertical column, contains elements with similar properties due to having the same number of electrons in their outermost shell.

For instance, group 1 elements (also known as alkali metals) like francium (Fr) typically lose one electron, forming +1 ions ( Fr^{+}). Group 2 elements, like barium (Ba), lose two electrons to form +2 ions ( Ba^{2+}). On the other hand, group 17 elements (halogens) such as bromine (Br) gain one electron to form -1 ions ( Br^{-}).

The group number not only helps in predicting ion charges but also guides the understanding of the reactivity and properties of elements. Knowing the group can effectively predict how elements will interact in chemical reactions, forming various compounds.