Question

Identify the element represented by each of the following symbols and give the number of protons and neutrons in each: \((\mathbf{a})_{5}^{11} X(\mathbf{b})_{33}^{75} X(\mathbf{c})_{36}^{86} X(\mathbf{d}) \frac{67}{30} X\).

Short answer

The elements represented by the symbols are: (a) Boron (B) with 5 protons and 6 neutrons, (b) Arsenic (As) with 33 protons and 42 neutrons, (c) Krypton (Kr) with 36 protons and 50 neutrons, (d) Zinc (Zn) with 30 protons and 37 neutrons.

Step-by-step solution

Identify the elements

For each symbol, we can find the element using the periodic table by looking up the atomic number. Atomic number is the subscript of the symbol, and it represents the number of protons in the nucleus of the element.

(a) Element with atomic number 5

In the periodic table, the element with the atomic number 5 is Boron (B).

(b) Element with atomic number 33

In the periodic table, the element with the atomic number 33 is Arsenic (As).

(c) Element with atomic number 36

In the periodic table, the element with the atomic number 36 is Krypton (Kr).

(d) Element with atomic number 30

In the periodic table, the element with the atomic number 30 is Zinc (Zn). Now that we have identified the elements, we can determine the number of protons and neutrons for each one.

Find the number of protons and neutrons

The atomic number (subscript) gives the number of protons in the element, and the mass number (superscript) gives the total number of protons and neutrons. To find the number of neutrons, we can subtract the atomic number (number of protons) from the mass number.

(a) Number of protons and neutrons for Boron

Boron has an atomic number of 5, so it has 5 protons. Its mass number is 11, so it has 11 - 5 = 6 neutrons.

(b) Number of protons and neutrons for Arsenic

Arsenic has an atomic number of 33, so it has 33 protons. Its mass number is 75, so it has 75 - 33 = 42 neutrons.

(c) Number of protons and neutrons for Krypton

Krypton has an atomic number of 36, so it has 36 protons. Its mass number is 86, so it has 86 - 36 = 50 neutrons.

(d) Number of protons and neutrons for Zinc

Zinc has an atomic number of 30, so it has 30 protons. Its mass number is 67, so it has 67 - 30 = 37 neutrons. In conclusion, the elements and their respective number of protons and neutrons are: (a) Boron (B): 5 protons, 6 neutrons (b) Arsenic (As): 33 protons, 42 neutrons (c) Krypton (Kr): 36 protons, 50 neutrons (d) Zinc (Zn): 30 protons, 37 neutrons.

Key concepts

Atomic Number

In chemistry, the atomic number is a fundamental concept that helps us understand the identity of an element. Defined as the number of protons found in the nucleus of an atom, the atomic number is critical because it determines the type of element. Each element on the periodic table has a unique atomic number, which serves as its identifier.

• For example, if an element has an atomic number of 5, like Boron, it means there are 5 protons in every atom of Boron.
• This is crucial because the atomic number not only identifies the element but also defines its position on the periodic table.

Remember, the atomic number is written as a subscript to the left of the element symbol. Knowing the atomic number allows chemists and students alike to identify and work with elements confidently.

Mass Number

The mass number is another key concept in understanding atomic structure. It represents the total number of protons and neutrons in an atom's nucleus. Unlike the atomic number, which only counts protons, the mass number gives us insight into the overall mass and structure of the atom.

• The mass number is usually written as a superscript to the left of the element symbol.
• For instance, in the case of Krypton with a mass number of 86, this means the sum of protons and neutrons equals 86.

When facing chemical problems, especially ones involving isotopes and elements, the mass number is essential. By knowing the mass number, we can deduce not only the number of neutrons but understand the atomic mass more precisely.

Neutrons

Neutrons are subatomic particles found in an atom's nucleus along with protons. Unlike protons, which have a positive charge, neutrons have no charge, making them neutral. This neutrality allows neutrons to act as a buffer, mitigating the repulsive forces between positively charged protons in the nucleus. Understanding neutrons is necessary for grasping the full picture of atomic structure.

• To figure out the number of neutrons in an atom, subtract the atomic number from the mass number. For instance, Zinc which has a mass number of 67 and atomic number of 30, contains 37 neutrons: 67 - 30 = 37.
• Neutrons play a critical role in the stability of an atom. Isotopes, which are variations of elements, often differ in their number of neutrons.

Recognizing the role of neutrons can help understand atomic stability, isotopic variations, and nuclear properties of elements.