Question

Refer to the periodic table and select the symbol of the element that fits each of the following descriptions: (a) the Group VA/15 semimetal in the fifth period (b) the sixth-period representative element with properties similar to Sr (c) the fifth-period transition element with properties similar to Ti (d) the lighter-than-air noble gas used in blimps and party balloons

Short answer

(a) Sb, (b) Ba, (c) Zr, (d) He

Step-by-step solution

Identify Group VA/15 Semimetal in Fifth Period

The Group VA/15 elements are part of the 15th column in the periodic table and include both non-metals and semimetals. In the fifth period, the semimetal (metalloid) in this group is Antimony (Sb).

Identify Sixth-Period Representative Element Similar to Sr

Strontium (Sr) is an alkaline earth metal located in Group 2 (IIA) of the periodic table. To find a sixth-period element similar to Sr, we look for another alkaline earth metal in the sixth period. This element is Barium (Ba).

Identify Fifth-Period Transition Element Similar to Ti

Titanium (Ti) is a transition metal in Group 4 of the periodic table. In the fifth period, the element with similar properties belonging to Group 4 is Zirconium (Zr).

Identify Lighter-Than-Air Noble Gas

The lighter-than-air noble gas typically used in blimps and party balloons is Helium (He), which is much lighter than air and non-flammable.

Key concepts

Chemical Groups

The periodic table is organized into vertical columns known as chemical groups or families. Each group contains elements that share similar chemical properties. This is due to the fact that elements in the same group have the same number of valence electrons. These shared characteristics allow chemists to predict the behavior of elements during chemical reactions. For instance:

• Group 1 elements are known as alkali metals and are very reactive, especially with water.
• Group 17 elements are called halogens and are also highly reactive, particularly with metals.
• Group 18 elements, known as noble gases, are inert and rarely participate in chemical reactions.

Understanding these groups helps us easily locate and identify elements based on their properties.

Element Symbols

Element symbols are shorthand notations used to represent chemical elements. These symbols usually consist of one or two letters, with the first letter always capitalized. This system was adopted for its simplicity and universality. For example:

• Hydrogen is represented as H.
• Oxygen is denoted by O.
• Gold is represented by the symbol Au, derived from its Latin name 'Aurum'.

These symbols are universally recognized, making them essential for scientific communication. They help condense information, making it easier to work with chemical equations and understand the periodic table.

Representative Elements

Also known as main group elements, representative elements include those found in Groups 1, 2 and 13-18 of the periodic table. These elements are key to understanding basic chemical principles as they have a wide range of properties and uses:

• Alkali metals (e.g., Na, K) are highly reactive metals.
• Alkaline earth metals (e.g., Mg, Ca) also have significant reactivity.
• Halogens (e.g., Cl, Br) are reactive non-metals that combine readily with metals to form salts.

These elements provide a broad understanding of chemical reactivity and trends across the periodic table. The study of representative elements is fundamental to learning chemistry.

Noble Gases

Noble gases, found in Group 18 of the periodic table, include elements such as Helium (He), Neon (Ne), and Argon (Ar). These gases are characterized by their complete valence electron shells, which make them extremely stable and unreactive. Noble gases have a variety of applications due to their properties:

• Helium is lighter than air, commonly used in balloons and airships.
• Neon is used in bright, glowing signs visible from long distances.
• Argon provides an inert atmosphere for welding and in incandescent light bulbs.

Their lack of reactivity makes them unique, providing valuable applications in both industrial and commercial fields. Understanding the role and properties of noble gases is key to appreciating their importance in everyday life.