The force that holds the electrons and protons together is the electromagnetic force.

Also, neutrons and protons are made up of tinier particles called quarks. And it is the quarks that exchange force carrying particles between each other to give rise to the strong force. The strong force also attracts protons to protons or neutrons to neutrons.

Protons and electrons stick to each other as much as they can, but kinetic energy and quantum mechanics keep them from holding still. Protons and electrons are attracted to each other because the positive electric charge of the proton is attracted to the negative charge of the electron.

Unlike the proton which has a positive charge, the neutron has no electrical charge and does not attract an electron to the atom. Although neutrons are not necessary for attracting electrons, they are required to space protons in the atomic nucleus.

Electrons have a negative charge. The charge on the proton and electron are exactly the same size but opposite. Neutrons have no charge. Since opposite charges attract, protons and electrons attract each other.

Thus neutrons repel each other but are attracted to protons.

Electrons move freely within the structure of an atom but protons are bound in the nucleus and therefore immobile. Conductivity will therefore occur when electrons move from one atom to another and not protons due to their immobility.

Inside the nucleus, the attractive strong nuclear force between protons outweighs the repulsive electromagnetic force and keeps the nucleus stable. Outside the nucleus, the electromagnetic force is stronger and protons repel each other.

electrons determine the atom’s size. With electrons on the surface, atoms repel one another when they come too close. Thus, electrons determine the space that an atom occupies. The mass number of an atom is 15, and its atomic number is 7.

The actual trends that are observed with atomic size have to do with three factors. These factors are: The number of protons in the nucleus (called the nuclear charge). The number of energy levels holding electrons (and the number of electrons in the outer energy level).

Atomic size gradually decreases from left to right across a period of elements. This is because, within a period or family of elements, all electrons are added to the same shell. However, at the same time, protons are being added to the nucleus, making it more positively charged.

So all the atoms of a given element have the same energy levels because they have the same numbers of electrons and protons. For example all hydrogen atoms have the same energy levels.

Originally Answered: Does two electrons in same orbital has same energy? Yes, they do. In fact, they share three quantum numbers (prime quantum number(same shell), azimuthal quantum number(same subshell) and magnetic quantum number(same orbital) – these quantum numbers determine electron’s energy.

Valence electrons

Electrons at higher energy levels, which are farther from the nucleus, have more energy. They also have more orbitals and greater possible numbers of electrons. Electrons at the outermost energy level of an atom are called valence electrons.

Although these electrons all have the same charge and the same mass, each electron in an atom has a different amount of energy. Electrons with the lowest energy are found closest to the nucleus, where the attractive force of the positively charged nucleus is the greatest.

1s 2s 2p 3s 3p represents the electron orbital energy levels.

We have s, p, d, and f sublevels.

After the 4f orbitals are filled, boxes are shown for the rest of the elements formed by adding 5d and 6p electrons. The seventh period contains boxes for the elements formed by filling the 7s, the 5f (the actinide series shown below the table), and finally the 6d sublevels.

There are four types of orbitals that you should be familiar with s, p, d and f (sharp, principle, diffuse and fundamental).

In the 1st energy level, electrons occupy only in the s sublevel, so there is no d sublevel. In the 3rd energy level, electrons occupy only the s, p, and d sublevels, so there is no f sublevel.

ℓ=2 is the d orbital. You cannot have ℓ=3 when n=3, which is the quantum number way of expressing why 3f doesn’t exist.

Because the quantum number n must be superior to angular momentum quantum number. In the 2nd energy level, electrons are placed only in the ‘s’ and ‘p’ sublevels, so there is no ‘d’ orbital. So, 2d orbital can’t exist.

Therefore, the 1p orbital doesn’t exist. In the second shell, both 2s and 2p orbitals exist, as it can have a maximum of 8 electrons. In the third shell, only the 3s, 3p and 3d orbitals exist, as it can hold a maximum of 18 electrons. Therefore, the 3f orbitals do not exist.