1. define
massnumber
The mass number is the total number of protons and neutrons in an atomic nucleus . It is also known as the atomic mass number or nucleon number. The mass
number is written either after the element name or as a superscript to the left of an element’s symbol . For example, the most common isotope of carbon is carbon12, or
12C, which has 6 protons and 6 neutrons. The full isotope symbol would also have the atomic number (Z) as a subscript to the left of the element symbol directly
below the mass number: 126C .
The mass number is different for each isotope of a given chemical element, and the difference between the mass number and the atomic number gives
2.define atomic number
The atomic number is the number of protons in the nucleus of an atom, which is unique to each element and determines its place in the periodic table . It is also
known as the proton number and is denoted by the symbol Z in atomic notation . The atomic number is important because it identifies the element and determines its
properties. For example, the number of electrons in a neutral atom is equal to the atomic number, which defines the atom’s electron configuration and the nature of its
valence electron shell . The periodic table is arranged in order of increasing atomic number . The following table lists the atomic numbers of the first 30 elements in the
periodic table:
Hydrogen 1 Helium
3.define the conductor with respect to their conductivity properties
A conductor is a material that allows electric charge to flow through it with little resistance . This property of conductors that allows them to conduct electricity is
known as conductivity . The flow of electrons in a conductor is known as the electric current . Metals such as copper, silver, gold, aluminum, and iron are good
conductors of electricity because they have many free electrons that can move easily when an electric field is applied . Conductors are used for making wires, cables,
circuits, and other devices that carry electric current [^
4.define a
semiconductor
A semiconductor is a material that has an electrical conductivity value falling between that of a conductor, such as copper, and an insulator, such as glass . The most
common semiconductor material is silicon, which is used in the production of microchips and other electronic devices . Semiconductors are used in a wide range of
applications, including transistors, diodes, solar cells, and light-emitting diodes (LEDs) . The electrical conductivity of a semiconductor can be modified by introducing
impurities into the crystal structure, a process known as doping . When two differently doped regions exist in the same crystal, a semiconductor junction is created,
which is the basis of diodes, transistors, and most modern electronics . Some examples of semiconductors are silicon, germanium, and gallium arsenide User
5.define an insulator
An insulator is a material that does not allow the flow of electric charge through it easily . It is also known as a dielectric . Insulators are used to separate electrical
conductors and prevent the flow of current between them . Examples of insulators include rubber, glass, air, and plastic . Insulators are used in a variety of
applications, such as electrical wiring, power transmission, and electronic devices . The following table lists some examples of insulators and their applications: | **
5.state two types of semiconductor materials
There are several types of semiconductor materials, some of which are:
1. Elemental Semiconductors: These are semiconductors made up of a single element, such as silicon (Si), germanium (Ge), and tin (Sn) .
2. Compound Semiconductors: These are semiconductors made up of two or more elements, such as gallium arsenide (GaAs), indium phosphide (InP), and
cadmium sulfide (CdS) .
I hope this helps!
6. define donor atom as used in
semiconductors
In semiconductor physics, a donor atom is a dopant atom that, when added to a semiconductor, can form an n-type region . For example, when silicon (Si), having
four valence electrons, is to be doped as an n-type semiconductor, elements from group V like phosphorus (P) or arsenic (As) can be used because they have five
valence electrons . A dopant with five valence electrons is also called a pentavalent impurity . When substituting a Si atom in the crystal lattice, four of the valence
electrons of phosphorus form covalent bonds with the neighboring Si atoms but the fifth one remains weakly bonded. If that electron is liberated, the initially electro-
neutral donor becomes positively charged (ionized). At room temperature, the liberated electron can move around the Si crystal and carry a current, thus acting as a
charge carrier .
I hope this helps!.
7.state how n type semiconductors are
formed
N-type semiconductors are formed by doping a semiconductor material with impurities that have more valence electrons than the semiconductor material itself . The
most commonly used impurities for n-type doping are Group V elements such as phosphorus (P), arsenic (As), and antimony (Sb) . These impurities have five valence
electrons, one more than the four valence electrons of the semiconductor material, such as silicon (Si) or germanium (Ge) . When these impurities are added to the