Scientist use models to study atoms because you cannot either see or perceive directly what do atoms look like.
Models permit to explain in a simplified way how the atoms are constituted, and, so, figure out how they behave and how they are the bulding blocks of the matter (elements and compounds).
A model can be a drawing or structure with balls and sticks, which show in an idealized way what an atom is.
Since the scientists have discovered different facts about the atoms along the last 200 years the models of the atoms have also evolved.
The plum pudding model of the atom proposed by JJ Thompson was different of the nuclear model proposed by Rutherford, and Rutherford's was different from the planetary model proposed by Bohr, and this is different from the quantum model.
Explanation:
These Rocks shown in photographs are made of different types of minerals which have properties as follows:
●The color of the rock is grey, brown and yellow after it is ground into a powder its color is streak.
● The lustre of the rock tells how shiny the rocks are.
● Other properties include hardness, texture, shape, and size.
A.
cytoplasm
B.
flagella
C.
pili
D.
plasma membrane
E.
ribosomes
(2) a negative ion
(3) an atom in an excited state
(4) an atom in the ground state
Answer;
-(3) an atom in an excited state
Explanation;
-An electron in a sodium atom gains enough energy to move from the second shell to the third shell. The sodium atom becomes an atom in an excited state.
-Ground state is the lowest allowable energy state of an atom. When electrons are subjected to stimuli like heat, light or electricity an electron may jump to a higher energy level, which is the excited state. Excitation is the elevation in energy level above the baseline energy state.