Periodic Table With Atomic Mass and Atomic Number – Free PDF

The periodic table is one of the most iconic charts in the field of chemistry. It not only organizes all known elements in a coherent way but also provides a wealth of information about the properties of each element. Among these properties, atomic mass and atomic number are two fundamental concepts that are essential to understanding the nature of elements.

List of Atomic Mass and Atomic Number of the Elements

Understanding Atomic Number

The atomic number of an element, denoted by Z, is the number of protons in the nucleus of an atom of that element. This number is unique to each element and determines its position in the periodic table. For example, hydrogen has an atomic number of 1, meaning it has one proton in its nucleus, while carbon has an atomic number of 6, meaning it has six protons.

The atomic number is crucial because it defines the identity of an element. Changing the number of protons in an atom’s nucleus transforms it into a different element. For instance, if a hydrogen atom (1 proton) gains a proton, it becomes helium (2 protons).

Understanding Atomic Mass

Atomic mass, also known as atomic weight, is a measure of the average mass of atoms of an element, calculated using the relative abundance of isotopes in a naturally occurring element. It is usually expressed in atomic mass units (amu), where 1 amu is defined as one twelfth of the mass of a carbon-12 atom.

The atomic mass takes into account the masses of protons, neutrons, and electrons, although the mass of electrons is negligible compared to protons and neutrons. Because elements can have different isotopes, atoms of the same element with different numbers of neutrons. The atomic mass reflects an average value based on isotope distribution.

The Structure of the Periodic Table

The periodic table is arranged in rows (periods) and columns (groups) that reflect recurring trends in the properties of elements.

Here’s how the atomic number and atomic mass are typically displayed:

Atomic Number: Usually shown above the element symbol, it increases from left to right across a period.

Atomic Mass: Typically displayed below the element symbol, it tends to increase as you move down a group.

Periodic Trends

Several periodic trends are linked to atomic number and atomic mass:

Atomic Radius: Generally increases as you move down a group due to the addition of electron shells but decreases across a period as the increasing number of protons pulls electrons closer to the nucleus.

Ionization Energy: The energy required to remove an electron from an atom. It generally increases across a period due to higher nuclear charge holding electrons more tightly and decreases down a group as electrons are further from the nucleus.

Electronegativity: A measure of an atom’s ability to attract and bond with electrons. It increases across a period and decreases down a group.

Applications of the Periodic Table

The periodic table is not just a theoretical tool, it has practical applications across science and industry. Here are a few examples:

Predicting Chemical Reactions: By understanding the position of elements in the periodic table, chemists can predict how elements will react with each other.

Material Science: Helps in discovering and utilizing new materials, understanding their properties, and designing new compounds.

Medicine: Vital in developing pharmaceuticals and understanding biological processes at the molecular level.

References

1. Audi, G., & Wapstra, A. H. (1993). The 1993 atomic mass evaluation:(I) Atomic mass table. Nuclear Physics A, 565(1), 1-65.
2. DeMeo, S. (2006). Revisiting molar mass, atomic mass, and mass number: Organizing, integrating, and sequencing fundamental chemical concepts. Journal of chemical education, 83(4), 617.
3. Harbour, D. (2011). Valence and atomic number. Linguistic inquiry, 42(4), 561-594.