Atomic weight is equal to what?
VerifiedAnswer: Number of Protons + Number of Neutrons
Explanation:
The atomic weight (also called atomic mass) of an element represents the total mass of an atom and is calculated by adding the number of protons and neutrons present in the nucleus. This fundamental concept helps us understand the basic structure of atoms and is essential for various calculations in chemistry.
To understand this better, let's look at the components of an atom. Every atom consists of three main particles: protons (positively charged), neutrons (neutral), and electrons (negatively charged). The protons and neutrons are located in the central region called the nucleus, while electrons orbit around the nucleus in different energy levels.
Since protons and neutrons have approximately the same mass (about 1 atomic mass unit each), and electrons have negligible mass compared to them (approximately 1/1836 of a proton's mass), we only consider protons and neutrons when calculating atomic weight. The mass contribution of electrons is so small that it doesn't significantly affect the overall atomic weight.
For example, let's consider a carbon atom with 6 protons and 6 neutrons. Its atomic weight would be 6 + 6 = 12 atomic mass units. Similarly, an oxygen atom with 8 protons and 8 neutrons would have an atomic weight of 8 + 8 = 16 atomic mass units.
It's important to note that while the number of protons remains constant for a particular element (this defines the element's identity), the number of neutrons can vary, creating different isotopes of the same element. These isotopes will have different atomic weights but represent the same element chemically.
The atomic weight values you see on the periodic table are actually average atomic masses that account for all naturally occurring isotopes of an element and their relative abundances. However, for basic calculations and understanding, we use the simple formula: Atomic Weight = Number of Protons + Number of Neutrons.
