Question

Consider the following nuclear symbols. How many protons, neutrons, and electrons does each element have? What elements do \(\mathrm{A}, \mathrm{L},\) and \(\mathrm{Z}\) represent? (a) \(\frac{75}{33} \mathrm{~A}\) (b) \({ }_{23}^{51} \mathrm{~L}\) (c) \({ }_{54}^{131} \mathrm{Z}\)

Short answer

Question: Determine the number of protons, neutrons, and electrons in each of the following uncharged atoms: A: \(\frac{75}{33} \mathrm{~A}\) L: \({}_{23}^{51} \mathrm{~L}\) Z: \({}_{54}^{131} \mathrm{Z}\) Also, identify each element. Answer: Element A (Arsenic, As): Protons: 33 Neutrons: 42 Electrons: 33 Element L (Vanadium, V): Protons: 23 Neutrons: 28 Electrons: 23 Element Z (Xenon, Xe): Protons: 54 Neutrons: 77 Electrons: 54

Step-by-step solution

Identify the meaning of the nuclear symbols

Each nuclear symbol has two parts - the atomic number (Z) and the mass number (A). The atomic number gives the number of protons in the element's nucleus. The mass number of an element is determined by adding the number of protons and the number of neutrons. The number of electrons in an uncharged atom is equal to the number of protons.

Find the number of protons, neutrons, and electrons for element A

Given symbol: \(\frac{75}{33} \mathrm{~A}\) Atomic number (Z) = 33 (number of protons) Mass number (A) = 75 To find the number of neutrons, subtract the atomic number from the mass number: Neutrons = 75 - 33 = 42 Since the atom is uncharged, the number of electrons is equal to the number of protons: Protons = 33 Electrons = 33

Identify element A

Using the periodic table, we can find the element with atomic number 33. Element A is Arsenic (As).

Find the number of protons, neutrons, and electrons for element L

Given symbol: \({}_{23}^{51} \mathrm{~L}\) Atomic number (Z) = 23 (number of protons) Mass number (A) = 51 To find the number of neutrons, subtract the atomic number from the mass number: Neutrons = 51 - 23 = 28 Since the atom is uncharged, the number of electrons is equal to the number of protons: Protons = 23 Electrons = 23

Identify element L

Using the periodic table, we can find the element with atomic number 23. Element L is Vanadium (V).

Find the number of protons, neutrons, and electrons for element Z

Given symbol: \({}_{54}^{131} \mathrm{Z}\) Atomic number (Z) = 54 (number of protons) Mass number (A) = 131 To find the number of neutrons, subtract the atomic number from the mass number: Neutrons = 131 - 54 = 77 Since the atom is uncharged, the number of electrons is equal to the number of protons: Protons = 54 Electrons = 54

Identify element Z

Using the periodic table, we can find the element with atomic number 54. Element Z is Xenon (Xe). In conclusion, we have determined the protons, neutrons, and electrons for each of the given elements, and have identified them as Arsenic (As), Vanadium (V), and Xenon (Xe).

Key concepts

Atomic Number

In chemistry, the atomic number is a fundamental property of an element that defines its identity. Simply put, it is the number of protons in the nucleus of an atom. Since protons are positively charged, the atomic number also represents the amount of positive charge within the nucleus.

For example, in the given exercise, element A has an atomic number of 33. This means it has 33 protons in its nucleus, which is the characteristic signature of arsenic (As) on the periodic table. Similarly, the atomic numbers for elements L and Z are 23 and 54, defining them as vanadium (V) and xenon (Xe), respectively.

The beauty of the atomic number is that it's unique to each element. No two different elements can have the same atomic number, making it an essential tool for identifying the elements in chemical compounds or when working through problems such as the one we're examining.

Mass Number

While the atomic number is all about protons, the mass number dives into the combined count of protons and neutrons, which are collectively known as nucleons. The mass number gives us an approximation of the atomic mass, which is important when solving for the number of neutrons or understanding the weight of an atom.

In our problem, to calculate the mass number, you simply add the protons and neutrons. For example, element A has a mass number of 75. With 33 protons (from its atomic number), we can deduce it has 42 neutrons by subtracting the atomic number from the mass number (75-33=42).

Understanding mass number is crucial not just for identifying elements but also for studying isotopes—forms of an element with the same number of protons but a different number of neutrons, thus differing mass numbers.

Periodic Table Elements

The periodic table is a chemist's roadmap, displaying all known chemical elements in an organized way. Elements are arranged by increasing atomic number, which is why understanding the atomic number is so vital in chemistry. Elements are also grouped into categories based on their similarities in chemical behavior.

Each element on the periodic table includes its atomic number, chemical symbol, and mass number. In our exercise, once we know the atomic number, we can use the periodic table to identify the element: atomic number 33 is arsenic (As), 23 is vanadium (V), and 54 is xenon (Xe).

Furthermore, the periodic table helps us understand relationships between the properties of the elements and their structures. For instance, elements within the same group (column) usually have similar properties. This systematic layout not only aids us in memorizing element properties but also in predicting the behavior of elements during chemical reactions.