Problem 140 - Chemistry An Atoms First Approach

Question

Which of the following statements is(are) correct? a. The symbols for the clements magnesium, aluminum, and xenon are \(\mathrm{Mn}, \mathrm{Al},\) and \(\mathrm{Xe},\) respectively. b. The elements \(P, A s,\) and \(B i\) are in the same family on the periodic table. c. All of the following elements are expected to gain electrons to form ions in ionic compounds: Ga, Se, and Br. d. The elements \(\mathrm{Co}, \mathrm{Ni},\) and \(\mathrm{Hg}\) are all transition elements. e. The correct name for \(\mathrm{TiO}_{2}\) is titanium dioxide.

Step-by-Step Solution

Answer

The correct statements are b, d, and e.

Step 1: Statement a: Mg, Al, and Xe symbols

The given symbols are Mn, Al, and Xe. To verify their correctness, let's check the periodic table: - Mg (not Mn) is the symbol for Magnesium - Al is the symbol for Aluminum - Xe is the symbol for Xenon So, statement a is incorrect.

Step 2: Statement b: P, As, and Bi elements' family

Let's check the periodic table to see if these elements belong to the same family: - P is Phosphorus, which belongs to Group 15 - As is Arsenic, which also belongs to Group 15 - Bi is Bismuth, which, too, belongs to Group 15 All of these elements are in the same family (Group 15), so statement b is correct.

Step 3: Statement c: Ga, Se, and Br gaining electrons

In general, metals lose electrons and non-metals gain electrons when forming ions in ionic compounds. Let's find out whether these elements are metal or non-metal: - Ga is Gallium, which is a metal - Se is Selenium, which is a non-metal - Br is Bromine, which is a non-metal Since Ga is a metal, it would lose electrons instead of gaining them. So, statement c is incorrect.

Step 4: Statement d: Co, Ni, and Hg being transition elements

Transition elements are located in the d-block of the periodic table. Let's verify the placement of these elements: - Co is Cobalt, which is in the d-block - Ni is Nickel, which is also in the d-block - Hg is Mercury, which is in the d-block as well All of these elements are transition elements (located in the d-block), so statement d is correct.

Step 5: Statement e: Name of TiO2

TiO2 is a compound containing Titanium (Ti) and Oxygen (O). To name the compound, look at the positive and negative ions present: - Ti is Titanium, which forms a +4 ion - O is Oxygen, which forms a -2 ion Since there are two Oxygen atoms, the compound will have a balanced charge. In naming the compound, we use prefixes to indicate the number of atoms. For this compound, we have: - Titanium: No prefix, as there is only one Ti atom - Oxygen: "di" prefix, as there are two O atoms Hence, the name is Titanium Dioxide, and statement e is correct. In conclusion, the correct statements are b, d, and e.

Key Concepts

Transition Elements

Transition elements are fascinating components of the periodic table, nestled within the d-block. These elements are known for their unique ability to form compounds with vivid colors, due to the d-d electron transitions. A classic example of transition elements includes Cobalt (Co), Nickel (Ni), and Mercury (Hg), all known for their diverse metallic properties.
What sets these elements apart is their ability to form multiple oxidation states. This can lead to the formation of various ionic compounds with different charges. Due to partially filled d-orbitals, they show catalytic properties, which are quite useful in industrial processes such as in the manufacture of fertilizers and the purification of hydrogen. Transition metals are also great conductors of heat and electricity, making them indispensable in electronics.

Ionic Compounds

Ionic compounds are formed when metals transfer electrons to non-metals, producing charged ions that are bound together by electrostatic forces. A simple example is sodium chloride (NaCl), commonly known as table salt.
The key here is electronegativity, or an element's ability to attract electrons from another element. In ionic compounds, one element (a metal) usually loses electrons to become a positively charged cation, and the other element (a non-metal) gains electrons to become a negatively charged anion. For instance, in the compound TiO extsubscript{2}, Titanium acts as the metal and transfers electrons to Oxygen, forming a stable ionic compound.

• Metals: Tend to lose electrons
• Non-metals: Tend to gain electrons

The arrangement in ionic compounds results in a crystalline structure, which gives them high melting and boiling points, as well as the ability to dissolve in water and conduct electricity when dissolved or melted.

Chemical Symbols

Chemical symbols serve as universal shorthand to represent elements. Each symbol is a direct reflection of the element's name, based often on the Latin name. For instance:

• Magnesium is represented as Mg, not to be confused with Mn which stands for Manganese.
• Aluminum is denoted as Al, and Xenon as Xe.

Understanding chemical symbols is crucial for correctly communicating in chemistry, allowing scientists to write concise and clear chemical formulas. These symbols range from single letters like H for Hydrogen to two letters such as Au for gold. Mistaking one element for another can lead to significant misinterpretations in chemical equations, as can be seen with the difference between Arsenic (As) and Sodium (Na), which have drastically different properties and behaviors.

Metal and Non-Metal

In the periodic table, elements are categorized into metals and non-metals, each with distinct properties. Metals, such as Gallium (Ga), tend to be good conductors of electricity and heat, have a shiny appearance, and are malleable. They lose electrons easily to form cations.
Non-metals, such as Selenium (Se) and Bromine (Br), usually do not conduct electricity well and are not malleable. They typically gain electrons, forming anions in ionic compounds. The contrast between these two types of elements is fundamental to understanding how compounds form. For instance,

• Metals: Lose electrons, form positive ions
• Non-metals: Gain electrons, form negative ions

This distinction helps in predicting chemical reactions and properties of substances, aiding scientists and students in visualizing how elements interact within compounds.