Problem 37 - Chemistry: The Central Science

Question

For each of the following elements, write its chemical symbol, locate it in the periodic table, and indicate whether it is a metal, metalloid, or nonmetal: (a) chromium, (b) helium, (c) phosphorus, (d) zinc, (e) magnesium, (f) bromine, (g) arsenic.

Step-by-Step Solution

Answer

(a) Chromium: Chemical symbol is Cr, located in group 6 and period 4, classified as a metal. (b) Helium: Chemical symbol is He, located in group 18 and period 1, classified as a nonmetal. (c) Phosphorus: Chemical symbol is P, located in group 15 and period 3, classified as a nonmetal. (d) Zinc: Chemical symbol is Zn, located in group 12 and period 4, classified as a metal. (e) Magnesium: Chemical symbol is Mg, located in group 2 and period 3, classified as a metal. (f) Bromine: Chemical symbol is Br, located in group 17 and period 4, classified as a nonmetal. (g) Arsenic: Chemical symbol is As, located in group 15 and period 4, classified as a metalloid.

Step 1: (a) Chromium

Chromium's chemical symbol is Cr. Locate it in the periodic table, by finding the 24th element, as Chromium has an atomic number of 24. Chromium is found in group 6 and period 4. It is classified as a metal.

Step 2: (b) Helium

Helium's chemical symbol is He. Locate it in the periodic table, by finding the 2nd element, as Helium has an atomic number of 2. Helium is found in group 18 and period 1. It is classified as a nonmetal.

Step 3: (c) Phosphorus

Phosphorus's chemical symbol is P. Locate it in the periodic table, by finding the 15th element, as Phosphorus has an atomic number of 15. Phosphorus is found in group 15 and period 3. It is classified as a nonmetal.

Step 4: (d) Zinc

Zinc's chemical symbol is Zn. Locate it in the periodic table, by finding the 30th element, as Zinc has an atomic number of 30. Zinc is found in group 12 and period 4. It is classified as a metal.

Step 5: (e) Magnesium

Magnesium's chemical symbol is Mg. Locate it in the periodic table, by finding the 12th element, as Magnesium has an atomic number of 12. Magnesium is found in group 2 and period 3. It is classified as a metal.

Step 6: (f) Bromine

Bromine's chemical symbol is Br. Locate it in the periodic table, by finding the 35th element, as Bromine has an atomic number of 35. Bromine is found in group 17 and period 4. It is classified as a nonmetal.

Step 7: (g) Arsenic

Arsenic's chemical symbol is As. Locate it in the periodic table, by finding the 33rd element, as Arsenic has an atomic number of 33. Arsenic is found in group 15 and period 4. It is classified as a metalloid.

Key Concepts

Chemical Symbols

Chemical symbols are shorthand representations of the names of the chemical elements, typically consisting of one or two letters from their English or Latin names. For instance, the symbol for Hydrogen is 'H', which reflects its name, while Sodium is represented as 'Na', derived from its Latin name 'Natrium'. It's essential to learn these symbols as they form the universal language of chemistry, enabling clear and concise communication between scientists across the globe.

Here are some tips to help you master the chemical symbols:

• Get familiar with the first one or two letters of the element's name, as most symbols are derived from them, like Carbon is 'C' and Oxygen is 'O'.
• Remember the exceptions, such as 'K' for Potassium (from 'Kalium') and 'Au' for Gold (from 'Aurum').
• Practice with flashcards or quizzes that can reinforce your memory through repetition and active recall.

Understanding chemical symbols is not only fundamental in following the steps of a chemical reaction but also in identifying elements within the periodic table quickly.

Metals, Metalloids, Nonmetals

The periodic table provides a structured way to classify elements as metals, metalloids, or nonmetals. Metals are typically found on the left and in the middle of the periodic table and are known for their shiny appearance, malleability, ductility, and excellent conductivity of heat and electricity. Examples include Iron (Fe), Copper (Cu), and Zinc (Zn).

Nonmetals are located mostly on the right side of the table and are characterized by their lack of metallic luster, poor conductivity, and they are generally brittle when solid. Vital nonmetals include Oxygen (O) and Nitrogen (N).

Metalloids possess a unique combination of metal and nonmetal properties, making them semiconductors, valuable in the electronic industry. Silicon (Si) and Arsenic (As) are typical examples. You can generally find metalloids along the dividing line between metals and nonmetals on the periodic table.

To categorize an element:

• Consider its physical and chemical properties.
• Look at its location on the periodic table; near the metalloids' line, it might be a metalloid, otherwise, if it aligns with either the left side or the right side, it could be a metal or nonmetal accordingly.

The differences in properties of these classifications are crucial for predicting the behavior of elements in reactions and their applications in various technologies.

Element Groups and Periods

The periodic table's grid-like structure is composed of rows called 'periods' and columns known as 'groups' or 'families'. Each period corresponds to the highest energy level of the electron orbitals that are occupied by electrons for the elements within that row. As you move from left to right across a period, each element has one more proton and is one electron more than the element before it.

Groups are the vertical columns. Elements within the same group share similar chemical properties because they have the same number of electrons in their outermost shell. For instance, Group 1 elements, known as alkali metals, are highly reactive and have just one electron in their outer shell.

To delve into how this helps you understand chemistry:

• By knowing the period, you can determine the energy levels of electrons in an atom.
• Understanding the group can help predict how an element will react with others.
• Remember that certain groups have special names, like Group 17 elements, which are called halogens, and Group 18, the noble gases, to help you recognize patterns of reactivity and characteristics.

Grasping the concept of groups and periods is essential for understanding the trends in the periodic table, such as ionization energy, atomic radius, and electronegativity, which further explain the behavior of elements in chemical reactions.