Isotopes are atoms that have a different number of neutrons than a different isotope. Allotropes are crystals that have a different atomic structure than a different allotrope.
You can see that allotropes and isotopes are completely different and really have no relationship to each other at all. But if you were confused about their difference, you may not have learned much about isotopes and allotropes. Each element on the periodic table is defined by the number of protons it has. For example, carbon has atomic number 6, so it has 6 protons. Any atom with 6 protons is a carbon atom.
Atoms are composed of protons, electrons, and neutrons. In most cases, atoms will be electrically neutral, so there will be enough electrons to match the protons 6, for carbon.
At first glance, you might think there could be any number of neutrons to match the protons. Or perhaps you might think there should be some rule, like 1 neutron per proton. The actual answer is somewhere in the middle. However, some isotopes will be more stable than others. Carbon, for example, can occur with 6 protons and 6, 7, or 8 neutrons. When naming isotopes, we use the atomic weight. The atomic weight is just the number of protons plus the number of neutrons. Carbon always has 6 protons, so 6 more neutrons and it will be Carbon Carbon has 7 neutrons, and Carbon has 8 neutrons.
There is also Carbon-8 to Carbon, but these can only be made in a laboratory and they are very unstable. Some isotopes will be more stable than others. In carbon, carbon is much more stable and abundant than carbon or carbon Carbon is unstable but has a very long half-life more on this in the next section. Isotopes are the reason that the atomic weights on the periodic table are not nice whole numbers.
Carbon weighs exactly 12 amu, carbon weighs 13 amu, etc. In other words, almost all carbon is carbon, but there is enough carbon and carbon to increase the average weight of carbon to Similarly, hydrogen has an atomic weight of 1. Most hydrogen is hydrogen-1 protium , but there are small amounts of hydrogen-2 deuterium and hydrogen-3 tritium. These isotopes of hydrogen get fancy names because they each have unique applications.
In general, stable isotopes behave pretty much the same. Sulfur in nature is found as S 8 units. These units are composed of eight sulfur atoms. Here, one sulfur atom is bonded to two other sulfur atoms forming a cyclic structure. These cyclic structures can be either in rhombic structure, needle form Monoclinic or orthorhombic form. The general structure of S 8 is the crown structure. Figure Crown structure of S8. Allotropy is defined for molecules in the physical state. Therefore, liquid water and ice are not allotropes even though both are composed of only water molecules H 2 O.
Isotopes are different forms of atomic structures of the same chemical element. Generally, an atom is made out of a nucleus and an electron cloud surrounding this nucleus. The nucleus is composed of protons and neutrons whereas the electron cloud is composed only of electrons. An element is composed of a unique number protons. The atomic number of an element is the number of protons. Therefore, each chemical element has a unique atomic number.
The periodic table of elements is built based on the atomic numbers of elements. Here, the chemical elements are arranged in the ascending order of the atomic number. However, the number of neutrons present in the nucleus is not a unique value for elements.
The atoms of the same element may have a different number of neutrons in their nucleus. These atoms are called isotopes. The isotopes of a particular element can be either stable or unstable. Unstable isotopes may undergo radioactive decay to obtain a stable form. Some of the most common Isotopes are given below. The atomic number of Hydrogen is 1.
Therefore, it is composed of 1 proton. There are 3 common Isotopes of Hydrogen. They are Protium, Deuterium, and Tritium. Protium has no neutrons; Deuterium has one neutron and Tritium has two neutrons in their nucleus. Figure Isotopes of Hydrogen. Helium is composed of two protons. O2 is abundant than O3. Normally, in nature, some allotropes are more abundant than others because of their stability.
Phosphorus has three allotropes as red, white and black phosphorus. From these, red and white phosphorus are the most common. Allotropes differ from each other due to the atomic arrangement, the number of atoms, etc. Isotopes are different forms of atoms of the same chemical element. They are different from each other as they have a different number of neutrons. Since the neutron number is different, their mass number also differs. However, the isotopes of the same element have the same number of protons and neutrons.
Different isotopes are present in varying quantities, and we can give this as a percentage value called relative abundance. For example, hydrogen has three isotopes as protium, deuterium and tritium. Their number of neutrons and relative abundances are as follows. The number of neutrons a nucleus can hold differs from element to element. Among these isotopes, only some are stable. For instance, oxygen has three stable isotopes, and tin has ten stable isotopes.
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