Why does the atomic model keep changing?

2. what subatomic particles of an atom are in the nucleus?

3. where are the electrons located?

4. draw an atomic model below. it should contain 4 levels with full shells.

5. how many valence electrons does iron (fe) have? how do you know?

Answer no 1:

Models can be described as ideas which are predicted by scientists based on their findings. With new advancements and researches in science, they keep changing over time.

The ancient Greeks believed that an atom cannot change or cannot be broken.But as advancements were made in the scientific field, sub atomic particles were discovered. Hence, the atomic model will keep changing whenever new better models will be proposed.

Answer No 2:

There are two subatomic particles which are present in the nucleus:

Answer No 3:

Electrons can be described as the sub atomic particles carrying a negative charge. They are not present inside the nucleus of an atom like protons and neutrons. Electrons are smaller than protons and neutrons.

Electrons are present outside of the nucleus, in shells or orbits that surround the nucleus.

Answer No 4:

The atomic model to be drawn shall be of Iron (Fe). Iron has 26 electrons.

An atom of electron will have 2 electrons in its outer shell. 8 in the second shell, 14 in the third shell and two in the last shell.

Answer No 5:

The number of electrons present in the outermost shell of an atom make the valence electrons. The outermost shell of electron has 2 electrons, hence the number of valence electrons will be 2 for an iron atom (Fe).

the answer is b)3/8x+1