Author Archives: Abdul Wahab

Periodic Table

What is the Periodic table?

There is a total of 118 discovered elements. These elements differ from each other because of the atoms which constitute them. They have the different number of protons in their nucleus. Although, these elements differ from each other but they share some of the common properties with each other. Chemists study these properties and have classified the elements in a table according to their properties. This table is called periodic table.

How are elements organized in the Periodic table?

The Periodic table of elements is divided into columns and rows. Each Block of the periodic table represents a single element. Elements are organized according to their atomic number in such a way that the atomic number increase from left to right in each row. The rows of the periodic table are called periods and columns are called groups. The periodic table has 18 groups and 7 periods.


A group is also called a family of elements. Elements in each column have the same number of valence electrons (outermost electrons). For example, Sodium and Potassium are in the group I, so they both have one valence electrons. Groups also show how an element will behave. For example, the last group is the noble gas family (Helium and Fluorine etc.). The elements in the noble gas family have their valence shell complete, so they don’t react with other elements in normal conditions.


The periodic table has 7 periods, these are the horizontal rows. The atomic number of elements increase from left to right of the periods. With increasing atomic number their atomic radius also increases.

Check out the interactive periodic table to learn more about it

Fun Facts

  • J is the only letter which is not available in the periodic table. Because no any element is abbreviated with J.
  • The first group of elements is called Alkali metals family. Elements in this category are very reactive which includes sodium and potassium.
  • Hydrogen is not considered as the part of Group I elements. Because it resembles with multiple groups.
  • Oxygen is the most abundant element in the Earth’s crust.

Land Pollution

What is Land Pollution

Land pollution is a worldwide issue in these days. It is the unnecessary materials that contaminate and damage our land. You have probably seen garbage on the streets that are not cleaned very often. This garbage is also the form of land pollution.



Causes of Land Pollution

Land pollution is caused by many chemical substances that are spilled on the land. These chemical substances come from different sources. Some sources are:

  • Garbage: garbageGarbage is the waste product of the household. Around 250 million tons of garbage was produced by united states by the year 2010. That means each person was contributing 2 Kg of garbage per day. So, where this trash will go? Probably these waste products need some kind of land where they can be disposed. The place where garbage is disposed is called landfill. These landfills take the free land and cause many problems. Landfills release toxic gases that are harmful living things and ozone layer of the atmosphere.
  • Factories: All the factories around the world produce waste products. These waste products can be toxic chemicals that can highly damage the land. Many developed countries have regulations for properly disposing of the waste chemicals. While many countries don’t have regulations about it. In those countries, waste products are thrown in oceans, rivers, and surrounding land. India is the main example, where factory and drainage waste is disposed in rivers despite having many regulations.
  • Farming: Vegetables, fruits, wheat, and rice are grown to meet our food demand. Farming needs free land to grow crops. For this, forests are being destroyed to increase the land area for farming. Moreover, pesticides and chemical fertilizers are used for better yield of the crops. These chemicals also damage the surrounding land and the water supply.
  • Mining: Mining is used to obtain the coal and minerals from within the Earth. Mining involves digging of holes in the land, which also cause erosion of the land. Mines also release the harmful chemicals and gases that contaminate the land and the air.

Effects of Land Pollution

Land pollution damages our environment which is very harmful to all the living things. Increased land pollution can cause many diseases including cancer and skin infections. Pollutants often get absorbed in the land and mix with the ground water below the surface. Which further pollute the land.

Landfills are used to dispose of the waste products by burying them into the land. As a result, the surrounding land is damaged. Moreover, landfills also release methane gas which increases the effect of global warming.

How can you help?

You can help in many ways to reduce the land pollution. Here are few things to do:

  • Don’t produce too much trash. Try to use cups or glasses of drinking water, instead of using disposable plastic cups.
  • Don’t take disposable plastic bags for bringing grocery items to home. Try to purchase a permanent bag and bring your item in that.
  • If you see any trash (paper or plastics etc.) in your streets, try to pick them and throw in a recycle bin.
  • Try to grow new plants around your home and streets. They produce oxygen and consume carbon dioxide.


  • Plastic bottles and cups take almost 1 million years to decay. But, Styrofoam never decay.
  • Our Earth is losing 25 billion tons of rich soil each year.
  • Production of energy, food, and transportation cause 80% of the land pollution.


What is an Element?

An element is a substance which is made of the same kind of atoms. The smallest piece of an element is the single atom. The chemical elements combine together to produce new substances. All the matter you see around yourself is composed of these elements. For example Iron, Aluminum, oxygen, gold, silver, and hydrogen.


Silver bar

Atomic Number –  How elements are distinguished?

Each element has its own type of unique atoms. These atoms are classified according to the number of protons present in its nucleus. For example, if an atom contains 8 protons than it will be the atom of oxygen element. The number of protons present in an atom is known as its atomic number.

Discovered Elements

There are 118 discovered elements. These elements were discovered in different time periods. Some elements were known to human beings since ancient times e.g. Gold, copper, and Iron. While some are discovered recently. The elements are widely distributed in our universe. But, Hydrogen is the most abundant element found in the universe.

Families of the Elements

There are 118 discovered elements. It is hard to remember each element with its properties. So, atoms are grouped together according to their properties. Elements with similar properties are placed in their respective group. Here are few groups:

Alkali Metals: These are the most reactive elements. They have only one electron in their outermost shell (valence shell). This group of elements includes Lithium, Sodium, and Potassium.

Halogens: Halogens are deficient of one electron to complete their valence shell. When these elements react with metals, they produce different kinds of salts. This group of elements contains Fluorine, Chlorine, and Iodine.

Noble Gases: These are the gases whose valence shells are complete. Noble gasses don’t react with other elements in their normal state, that’s why they are called noble gases. This group of elements contains Helium, Neon, and Argon.

Periodic table

All the elements are listed according to their characteristics, properties, and behaviors into a table called the periodic table. The periodic table lists all the elements into the columns and rows. The columns are called groups and rows are called periods.


Periodic Table

Fun Facts

  • There are 118 discovered elements, out of which 94 are naturally occurring on the Earth. While other elements are prepared synthetically. There are 24 synthetic elements.
  • Hydrogen element is the most abundant element in the universe.
  • Our Sun is composed of 75% Hydrogen and 25% Helium.
  • Carbon is a unique element and an important constituent of living things. Carbon can produce 10 million different compounds by reacting with other elements.

Voltage, Current, and Resistance


Voltage is an electrical pressure, which forces the electric charges (electrons) to move in an electrical circuit. Voltage is measured in volts, abbreviated as ‘V’. To understand the concept of voltage, consider a water pump which is pumping the water. The pump pushes the water to flow in the pipes. The pump acts like the voltage and the water acts like charges.

However, it is not necessary that when the voltage is applied, the electric charges will flow (current). Charges need a complete closed path to flow.


Electric current is the number of electrons flowing through a point in a circuit. Consider a circuit, which is marked ‘A’ at a point. The number of electrons that will pass through the point ‘A’ in one second will be the current of the circuit. You can consider the current in a circuit as a flow of water in the pipes. The current in a circuit is caused by the voltage, much like the water flow in the pipes is caused by the pump. Electric current is measured in the amperes, sometimes called “amps”. It is denoted by the letter ‘I’.


Resistance, as the name suggests, provides the resistance to the electrical current. It always tries to stop the current from flowing. Every material around the world has resistance for electric current. Some materials have very small resistance, called conductors. While, other materials have very high resistance, called insulators. We use the conductors in the circuit for electric current to pass easily.

Resistance depends on the structure of the material:

  • If a material has more free electrons like metals, it will act as a conductor.
  • If a material has fewer free electrons like rubber, it will act as an insulator.

Relationship between Voltage, Current, and Resistance

The relationship between voltage, current, and resistance can be found from the ohm’s law:

V = I*R  ;              Here,  V = Voltage, I = Current, R = Resistance

See the Ohm’s Law for further information.

AC and DC

There are two types of current that flow in a circuit. One is called DC (Direct Current) and other is AC (Alternating Current).

  • DC: Direct current is the flow of electrons in one direction. Although, the magnitude of the current can decrease or increase but it will always flow in one direction in a circuit. Batteries and charger produce the DC.
  • AC: Alternating current doesn’t flow in one direction in a circuit. Instead, it changes its polarity (direction) constantly. The rate of changing polarity is called the frequency of AC. We all use AC current in our homes with 50 to 60 Hertz frequency. AC is often converted into DC by the chargers to charge your laptop and smart phone’s battery.

Interesting Facts

  • If the voltage is sufficient enough, electric current can pass through air. Lightning strikes, when the voltage builds enough to pass through air.
  • When current pass through a conductor, it produces a magnetic field around it.
  • Voltage is measured by a voltmeter. Whereas, current is measured by the ammeter.

Resistors, Capacitors, and Inductors

Electric circuits are used to provide a path to electric current. They commonly use three basic electrical components, which are resistors, capacitors, and insulators. They affect the electric current and changes the behavior of the circuit.


A resistor is an electrical component, which has a certain amount of resistance. Resistance is the measure of the opposition to electric current. The more resistance a resistor has, the lesser current will flow through it. Resistance is measured in the unit called ohms, and it is abbreviated with the Greek symbol Ω (omega).


Resistor symbol

Resistance is found by the using the ohm’s law. Which says that resistance in ohms is equal to voltage divided by current.

Resistance = Voltage/Current


R = V/I

Resistors are represented by a zigzag line in an electric circuit, and the letter ‘R’ is used in the equations.


Electric current is the flow of electric charges, much like the flow of water. As water can be stored, charges can also be stored. The electrical component that stores the electric charges is called capacitor. Capacitor’s ability to store the charge is called capacitance, which is measured in ‘Farads’ and abbreviated as ‘F’. The more capacitance a capacitor has, the more electric charge can be stored in it. Capacitors are represented by the two parallel plates in an electric circuit.


Capacitor symbol

The capacitance of a capacitor is found by the formula:

Capacitance = Charge Stored/Voltage


C = q/V ;              q = stored charge

V = Voltage of the capacitor


The opposition to change in current is called inductance, and an electrical component which has inductance is called inductor. Inductors are like the short circuits to the DC current, because DC current doesn’t change the magnitude. But, Inductors provide an opposition like a resistor to the AC current. Because AC current constantly change the magnitude and the polarity.


Inductor symbol

Inductance is measured in henrys and is abbreviated as ‘H’. But, it is denoted by ‘L’ in the equations. The symbol for the inductor is:

Interesting Facts

  • Conductance, represented by ‘G’ is opposite to the resistance.
  • Resistors are the basic ingredient of every electronic circuit.
  • Capacitors can’t store electrical charges in AC current. Because they constantly store and drain the charges as the polarity of AC reverses.