Question

Which of the following statements is(are) true? For the false statements, correct them. a. Most of the known elements are metals. b. Element 118 should be a nonmetal. c. Hydrogen has mostly metallic properties. d. A family of elements is also known as a period of elements. e. When an alkaline earth metal, A, reacts with a halogen, \(\mathrm{X}\), the formula of the covalent compound formed should be \(\mathrm{A}_{2} \mathrm{X}\)

Short answer

True statements: a False statements and corrections: b. Correction: Element 118 should be a noble gas. c. Correction: Hydrogen is a nonmetal with unique properties. d. Correction: A family of elements is also known as a group of elements. e. Correction: When an alkaline earth metal, A, reacts with a halogen, \(\mathrm{X}\), the formula of the ionic compound formed should be \(\mathrm{AX}_{2}\).

Step-by-step solution

a. Most of the known elements are metals.

This statement is true. Most of the known elements in the periodic table are indeed metals. This includes alkali metals, alkaline earth metals, transition metals, and various other metals.

b. Element 118 should be a nonmetal.

This statement is false. The correct statement should be: "Element 118 should be a noble gas." Element 118, known as oganesson (Og), is part of Group 18 in the periodic table. These elements are called noble gases, which are generally nonreactive and have full electron shells.

c. Hydrogen has mostly metallic properties.

This statement is false. The corrected statement should be: "Hydrogen is a nonmetal with unique properties." Hydrogen is in Group 1 of the periodic table and, while it has a single valence electron like alkali metals, it is considered a nonmetal due to its unique properties, such as low boiling and melting points, and the fact that it usually forms covalent bonds instead of ionic bonds.

d. A family of elements is also known as a period of elements.

This statement is false. The corrected statement should be: "A family of elements is also known as a group of elements." A family, or group, of elements refers to a vertical column in the periodic table where elements share similar chemical properties. A period, on the other hand, refers to a horizontal row in the periodic table.

e. When an alkaline earth metal, A, reacts with a halogen, \(\mathrm{X}\), the formula of the covalent compound formed should be \(\mathrm{A}_{2} \mathrm{X}\).

This statement is false. The corrected statement should be: "When an alkaline earth metal, A, reacts with a halogen, \(\mathrm{X}\), the formula of the ionic compound formed should be \(\mathrm{AX}_{2}\)." The alkaline earth metal (Group 2) will typically form a +2 cation by losing two electrons, while the halogen (Group 17) will form a -1 anion by gaining one electron. The formula for the resulting ionic compound should be \(\mathrm{AX}_{2}\), which maintains charge neutrality.

Key concepts

Metals

The periodic table is a treasure trove of metals, which make up the majority of elements. Metals are elements that usually have high electrical and thermal conductivity. They are shiny, malleable, and ductile. You’ll often find metals in groups such as the transition metals, alkali metals, and alkaline earth metals.
Metals are typically found on the left and in the center of the periodic table. They tend to lose electrons and form positive ions or cations in chemical reactions.
Some typical examples include:

• Copper (Cu) used in electrical wiring due to its conductivity.
• Iron (Fe), which is strong and used in construction.
• Gold (Au), valued for its rarity and luster in jewelry.

Overall, metals play a critical role in our daily life and are key players in the functionality of the periodic table.

Noble Gases

Noble gases, occupying Group 18 of the periodic table, stand out because of their unique nonreactivity. These gases include helium, neon, argon, krypton, xenon, and the relatively new oganesson.
They are characterized by their full outer electron shell, which makes them very stable and reluctant to participate in chemical reactions. Thus, they don't usually form compounds with other elements.
The noble gases are colorless, odorless, tasteless, and non-flammable. Some common applications include:

• Helium, which is lighter than air and used in balloons.
• Neon, famous for vibrant neon signs.
• Argon, used in lightbulbs to prevent general oxidation of the filament.

Their stability and lack of reactivity make them incredibly useful in various applications.

Alkaline Earth Metals

Alkaline earth metals belong to Group 2 in the periodic table and comprise beryllium, magnesium, calcium, strontium, barium, and radium. These metals share common features such as being shiny and somewhat reactive, though less so than alkali metals.
Alkaline earth metals are known for having two electrons in their outermost shell, which they readily lose to form cations with a charge of +2. This makes them essential in a wide array of chemical reactions.
Typical uses of alkaline earth metals include:

• Magnesium, valued for its strength-to-weight ratio, used in aerospace and automotive industries.
• Calcium, a crucial component of bones and teeth, also widely used in the manufacture of cement.
• Barium, used in medical imaging as a radiocontrast agent.

They form ionic compounds and are essential to many geological and biological processes.

Halogens

Found in Group 17, halogens are a group of highly reactive nonmetals, including fluorine, chlorine, bromine, iodine, and astatine. Their name means "salt-former," reflecting their tendency to form salts when bonded with metals.
Halogens have seven electrons in their outer shell, just one short of a full shell. This makes them very reactive as they strive to gain that last electron. Here are some highlights of halogens:

• Fluorine, the most reactive, is used in toothpaste to prevent dental cavities.
• Chlorine is utilized in water purification and the production of many disinfectants.
• Iodine is vital for thyroid health and is used as a disinfectant.

Reacting readily with metals to form ionic compounds like NaCl (common table salt), halogens are crucial for biological functions and industrial applications.