Skip to main content

Atomic number, Mass number and Atomic species

 Atomic number, Mass number and Atomic species

Atomic number or Nuclear charge 

(i) The number of protons present in the nucleus of the atom is called atomic number (Z). 
(ii) It was determined by Moseley as, 

V1/2 =a(z-b)

Where, v=X -  ray’s frequency

 Z= atomic number of the metal a & b are constant. 
(iii) Atomic number = Number of positive charge on nucleus = Number of protons in nucleus = Number of electrons in nutral atom.
 (iv) Two different elements can never have identical atomic number.

 Mass number 

Mass number (A) = Number of protons or Atomic number (Z) + Number of neutrons or Number of neutrons = A – Z .
 (i) Since mass of a proton or a neutron is not a whole number (on atomic weight scale), weight is not necessarily a whole number.
 (ii) The atom of an element X having mass number (A) and atomic number (Z) may be represented by a symbol, ZXA

Different types of atomic species

Isotopes

Given by Soddy

1.They are the atoms of a given element  which have the same Atomic number (Z) but different Mass number (A).

2.They have same number of protons and same number of electrons but  different number of neutrons.

3. They have same electronic confriguration , same chemical properties and same position in the periodic table but different physical properties. 

examples: 


 Isobars

Given by Aston 
1.They are the atoms of different elements which have the same Mass number (A) but different Atomic number(Z).
2.They have different number of electron , protons and neutrons but sum of number of protons and neutrons i.e. number of neucleons remains same .
3. They have different electronic configuration , chemical properties and the position in the periodic table. 
examples 

 Isotones

1.They are the atoms of different elements which have the same number of neutrons but different atomic number, mass number , number of protons and number of electrons.

2. They have the different electronic configuration, physical properties , chemical properties and position in the periodic table. 

examples 

Isodiaphers 

They are the atoms of different elements which have the same difference of the number of Neutrons and protons. 
examples 

Isoelectronic species 

They are the atoms of given element which have the same number of electrons and electronic configuration but different atomic numbet and mass number. 
examples 

Isosters 

they are the molecules which have the same number of atoms , number of electrons and physical properties and chemical properties. 
examples 



Labels:

Comments

Post a Comment

Popular posts from this blog

What is matter ?

What is matter ?    Matter is a term used in physics or chemistry to refer to anything that has mass and occupies space. In other words, it is the substance of which all physical objects are made. This includes everything we can see, touch, and interact with in the universe. Matter is composed of elementary particles, the most common of which are atoms and molecules. Atoms are the basic building blocks of matter, and they consist of a nucleus, composed of protons and neutrons, surrounded by electrons. Molecules, on the other hand, are groups of atoms chemically bonded together. There are four fundamental states of matter: 1. Solid: In solids, atoms or molecules are tightly packed and have a fixed shape and volume. The particles vibrate around fixed positions. 2. Liquid: Liquids have a definite volume but take the shape of their container. The particles in liquids are still close together, but they can move more freely than in a solid. 3. Gas: Gases have no fixed shape or volume and ca
Post a Comment
Read more

Molar : Understanding the Concept and Its Significance

Demystifying Molar: Understanding the Concept and Its Significance Introduction: In the field of chemistry, the concept of the mole, often referred to as "molar," serves as a fundamental unit of measurement. The molar is a crucial concept that allows scientists to quantify and understand the relationships between atoms, molecules, and reactions. In this blog, we will delve into the fascinating world of moles, exploring their definition, significance, and applications in various aspects of chemistry. What is a Molar? Simply put, a molar is a unit of measurement used in chemistry to quantify the amount of a substance. It provides a bridge between the microscopic world of atoms and molecules and the macroscopic world of everyday measurements. The molar is defined as the amount of a substance that contains as many entities (atoms, molecules, ions, etc.) as there are atoms in exactly 12 grams of carbon-12. This definition is based on Avogadro's number, which is approximately 6
Post a Comment
Read more

Unveiling the Science Behind Washing Powders: Insights from a Chemist

Unveiling the Science Behind Washing Powders: Insights from a Chemist Introduction: In our everyday lives, we encounter numerous challenges, and one that most of us can relate to is laundry. The quest for cleaner, fresher, and more vibrant clothes has led to the development of various laundry detergents, including the ever-popular washing powders. As a chemist, I find the science behind these powders fascinating. In this blog, we will delve into the intricate world of washing powders, exploring their composition, working mechanisms, and the chemical reactions that make them effective . 1. Composition of Washing Powders: Washing powders are complex mixtures of chemicals carefully formulated to remove dirt, stains, and odors from fabrics. The composition of washing powders typically includes the following key components:  a. Surfactants:  These are the primary cleansing agents in washing powders. Surfactants contain both hydrophilic (water-attracting) and lipophilic (oil-attracting) prop
Post a Comment
Read more