Universe is made from Atom

Atoms Are Building Blocks of everything visible in- the Universe:

Atoms: it is the smallest distinct unit of matter.
They are the basis for everything in the Universe.

Matter is composed of atoms.

Solids, Liquid, and Gases are the three states of matter, Solid is made of densely packed atoms, the liquid is loose packed atoms and gases have atoms that are spread out.
Super-small particles can be found in the pieces of atoms. These subatomic particles include nucleons, protons, and neutrons.

Mainly atoms consist of three Super -tiny particles:

The three basic parts of an atom: Electrons, Protons, and Neutrons.

Electrons are the smallest of the three particles that make up atoms.

Electrons are found in Shells or  Atomic-orbits that surround the nucleus of an atom.

Protons and neutrons are found in the nucleus.

There are almost 120 known elements in the periodic table. The atoms of different elements have different numbers of electrons, protons, and neutrons. 

Every element is unique and has an unique atomic number. 

That number tells you the number of protons in every atom of the element. The atomic number is also called the proton number. 

Charges of Atoms

Each atom is labeled with a "+", "-", or a "0." 

Those symbols refer to the charge of the particle. 

Have you experienced getting a shock from a socket, static electricity, or lightning by touching live electrical wires?Those are called electric charges. Similarly, charges are also found in tiny particles of matter. 

The Electron always has a "-", or negative charge.

The proton always has a "+", or positive, charge.

If the charge of an entire atom is "0", or neutral, there are equal numbers of positive and negative charges.

Neutral atoms have equal numbers of electrons and protons.

The third particle is the neutron. It has a neutral charge, also known as a charge of zero. 

Since the number of protons in an atom does not change, fewer or extra electrons can create a special atom called an ion. 

Cations have fewer electrons and have a positive charge. 

Anions have extra electrons that create a negative charge

Electrons are always moving.They spin very quickly around the nucleus of an Atom.

As the electrons move around, they move in any direction imagine — upwards, downwards, or sidewards, as long as they stay in their shell/orbits. Electrons are constantly spinning in those atomic shells and those shells or orbits, are at specific distances from the nucleus.

An electron in the first shell/ orbits are always closer to the nucleus than the electrons in the second shell. 
Shell Basics

1. The center of the atom is called the nucleus.
2. Electrons are found in areas called shells. A shell is sometimes called an energy level.
3. Shells are areas that surround the center of an atom. 
4. Each of those shells has a name (K, L, M...). 

Chemists identify these atomic shells as an "n" value, or the letters K, L, M, N, O, P, and Q.

The "K" shell is the one closest to the nucleus, and "Q" is the farthest away.

For simple atoms, those "n" values usually match the row number on the periodic table and are also known as energy levels.

The second description looks at how electrons act inside of the shells. 

There are certain patterns of movement. 

Chemists have described those patterns with the "l" value. The "l" values tell you what suborbital an electron is found in. 

You will see the lowercase letters s, p, d, f, g, and h for the suborbital. 

For example,the electron in a 
hydrogen (H) atom would have the values n=1 and l=0. The single electron would be found in the "K" shell and the "s" suborbital as 1s1. 

Helium (He) is still in the K shell (top row), but it has two electrons. The first electron would be 1s1 and the second would be 1s2. 

lithium (Li) at atomic number three with three electrons? It would be described as 1s2 2s1.  

Not all shells and sub-orbits hold the same number of electrons. 

For the first eighteen elements, there are some easy rules. The K shell only holds two electrons. 

The L shell only holds eight electrons. 

The M shell only holds eight electrons. 

The M shell can actually hold up to 18 electrons as you move to higher atomic numbers. 

The maximum number of electrons you will find in any shell is 32.