Question

What is the mass of a sodium atom in atomic mass units?

Short answer

The mass of a sodium atom is approximately 22.99 amu.

Step-by-step solution

Understand the concept of atomic mass units

An atomic mass unit (amu) is a standard unit of mass that quantifies mass on an atomic or molecular scale (atomic scale). It is defined as one twelfth of the mass of an unbound neutral atom of carbon-12 in its nuclear and electronic ground state, and it is a convenient way to express atomic and molecular masses.

Identify the element in question

The question asks for the mass of a sodium atom. Sodium is a chemical element with the symbol Na and atomic number 11.

Use the periodic table for atomic masses

The atomic mass of sodium, which can usually be found on the periodic table, is approximately 22.99 amu. This value is the weighted average mass of all naturally occurring isotopes of sodium.

Key concepts

Atomic Mass

The concept of atomic mass is essential in understanding chemistry. Atomic mass refers to the mass of an atom, typically expressed in atomic mass units (amu). This measurement helps scientists to compare the masses of different atoms conveniently. One amu is defined as one twelfth of the mass of a carbon-12 atom. Every element has a unique atomic mass, which is often a weighted average that takes into account all the isotopes of that element. Understanding atomic mass is crucial in chemistry as it allows for the calculation of molar masses in chemical reactions.

Sodium Atom

Sodium is a fascinating element that is highly reactive. Represented by the symbol Na and atomic number 11, sodium belongs to the alkali metals group on the periodic table. Its atoms have 11 protons in the nucleus and a single electron in the outermost shell, which makes them very reactive. Sodium is essential for many biological processes in living organisms, such as nerve impulse transmission and muscle contraction. The atomic mass of a sodium atom is roughly 22.99 amu, helping it play a significant role in various chemical reactions.

Periodic Table

The periodic table is an incredible tool for chemists that organizes all known elements. By arranging elements into rows and columns based on their atomic number, electron configuration, and recurring chemical properties, it offers a wealth of information. Each element's box within the table provides specific details including its atomic number, symbol, and atomic mass. This layout allows scientists to understand elemental relationships and predict chemical behavior. For example, the position of sodium on the periodic table indicates its properties and reactivity.

Atomic Scale

When dealing with atoms and molecules, the atomic scale is indispensable. This scale measures very small masses and distances, which is crucial for studies involving atoms. Since atoms are impossibly tiny to handle individually, terms like atomic mass units (amu) are used to bridge the gap between microscopic particles and macroscopic quantities we can measure and use in the lab. An amu provides a standard unit on the atomic scale, allowing scientists to express the masses of atoms and molecules in a manageable form, facilitating comparisons and calculations in chemistry.