Question

Which sets of atomic numbers are incorrect?

1. Identify the incorrect sets of chemical symbols.
2. Choose the accurate atomic numbers from the following options.
3. Select the valid combinations of atomic numbers.
4. Determine which sets of atomic numbers contain inaccuracies.

Answer 1

In Chemistry, atomic number and mass number are key to identifying elements and their isotopes, with atomic number defining the element and mass number representing the sum of protons and neutrons. To verify chemical symbols and atomic numbers, we must balance both sides of the equation and refer to the periodic table. Symbols for specific ions can be written based on their protons, electrons, charge, and mass number by finding the appropriate element with the given atomic number.

Step-by-step explanation:

The subject of this question is Chemistry, specifically dealing with concepts related to atomic structure and the periodic table. When determining the correctness of a set of atomic numbers or chemical symbols, it is essential to understand the definition of atomic number and mass number, as well as how isotopes of an element differ from one another. The atomic number is crucial because it defines the identity of an atom by indicating the number of protons present in the nucleus. Mass number, on the other hand, is the total number of protons and neutrons in the nucleus. Isotopes have the same atomic number but differ in mass number due to a different number of neutrons.

To answer the question correctly, one has to balance the atomic numbers and mass numbers, write the symbols of the relevant ions or nucleoids, and use the periodic table as a reference for correct atomic numbers. For example, isotopes always have the same atomic number but different mass numbers, and this is shown in the way we write the symbol of an element or ion.

Here are the symbols for the ions mentioned in the question:

(a) The ion with a 1+ charge, atomic number 55, and mass number 133 is Cs+ because cesium has the atomic number 55.

(b) The ion with 54 electrons, 53 protons, and 74 neutrons is I- because iodine has the atomic number 53.

(c) The ion with atomic number 15, mass number 31, and a 3- charge is P3- because phosphorus has the atomic number 15.

(d) The ion with 24 electrons, 30 neutrons, and a 3+ charge is Cr3+ because chromium has the atomic number 24.

Answer 2

The atomic number defines an element and its position on the periodic table, and it is essential for writing chemical symbols and balancing equations. The mass number, on the other hand, helps determine isotopes and consists of the total protons and neutrons in the atom's nucleus.

Step-by-step explanation:

To address the student's query, one must understand that the atomic number is crucial in identifying an element since it represents the number of protons in an atom's nucleus, which defines its chemical properties. For instance, the atomic numbers given (55, 53, etc.) must correspond to the correct element on the periodic table. Let's confirm the symbols for some specified ions:

• The ion with a 1+ charge, atomic number 55 (Cs), and mass number 133 is Cs+.
• The ion with 54 electrons, 53 protons (I), and 74 neutrons is I-.
• The ion with atomic number 15 (P), mass number 31, and a 3- charge is P3-.
• The ion with 24 electrons, 30 neutrons, and a 3+ charge corresponds to an element with atomic number 27, which is cobalt (Co), and its ion is Co3+.

Isotopes are atoms of the same element with the same atomic number but differing mass numbers due to variations in neutron count. The mass number of an element is the total count of protons and neutrons in its nucleus. A tin (Sn) atom with an atomic number of 50 and a mass number of 118 would thus have 68 neutrons. Notably, balancing chemical equations requires both the mass number and the atomic number to be equal on both sides of the reaction.