Rolando and Bianca's Temperate Decidous Forest Poster

The atomic models xD

Atomic theory proposed by John Dalton

Dalton's theory was based on the premise that the atoms of different elements could be distinguished by differences in their weights. He stated his theory in a lecture to the Royal Institution in 1803. The theory proposed a number of basic ideas:

1) All matter is composed of atoms

2) Atoms cannot be made or destroyed

3) All atoms of the same element are identical

4) Different elements have different types of atoms

5) Chemical reactions occur when atoms are rearranged

6) Compounds are formed from atoms of the constituent elements.

Using his theory, Dalton rationalised the various laws of chemical combination which were in existence at that time. However, he made a mistake in assuming that the simplest compound of two elements must be binary, formed from atoms of each element in a 1:1 ratio, and his system of atomic weights was not very accurate - he gave oxygen an atomic weight of seven instead of eight.

Atomic Model of Thomson

J. J. Thomson considered that the structure of an atom is something like a raisin bread, so that his atomic model is sometimes called the raisin bread model. He assumed that the basic body of an atom is a spherical object containing N electrons confined in homogeneous jellylike but relatively massive positive charge distribution whose total charge cancels that of the N electrons.

 

Rutherfor's Atomic Model

 

Ernest Rutherford publishes his atomic theory describing the atom as having a central positive nucleus surrounded by negative orbiting electrons. This model suggested that most of the mass of the atom was contained in the small nucleus, and that the rest of the atom was mostly empty space. Rutherford came to this conclusion following the results of his famous gold foil experiment. This experiment involved the firing of radioactive particles through minutely thin metal foils (notably gold) and detecting them using screens coated with zinc sulfide (a scintillator). Rutherford found that although the vast majority of particles passed straight through the foil approximately 1 in 8000 were deflected leading him to his theory that most of the atom was made up of 'empty space'.

Atomic model of Bohr

In 1913 Bohr proposed his quantized shell model of the atom to explain how electrons can have stable orbits around the nucleus. The motion of the electrons in the Rutherford model was unstable because, according to classical mechanics and electromagnetic theory, any charged particle moving on a curved path emits electromagnetic radiation; thus, the electrons would lose energy and spiral into the nucleus. To remedy the stability problem, Bohr modified the Rutherford model by requiring that the electrons move in orbits of fixed size and energy. The energy of an electron depends on the size of the orbit and is lower for smaller orbits. Radiation can occur only when the electron jumps from one orbit to another. The atom will be completely stable in the state with the smallest orbit, since there is no orbit of lower energy into which the electron can jump.

 
Rolando Zavala Gonzalez

(Na) Sodium

Sodium is present in almost all the potable water the companies sell in Monterrey, and we drink the water without thinking that we are drinkin also like 5mg of sodium per bottle (supposing the bottle has a volume of 500ml). Many companies around the world have search for the consequences of this substance, and the results were amazing, the recomended quantity of this substance per day is just about from 1100-3300 milligrams (mg) per day, this is the half of the sodium consumed by a tipical american now at days.

 This is a little dangerous for some people that have healthy problems in blood, heart, etc, because they have to purify the water they drink in order to hydrate theirselves.
This problem han't been stopped because is very expensive for the companies that sell water, separate completely the sodium from the H2O, so they just reduce the concentration of sodium to 5%, wich is kind of the standar nowadays.

This subsrance has not much impact in my daily life today, because I am young and do not have developed healthy problems, but for many other people that do have healthy problems, they may know about this, to prevent other diseases.

Rolando Zavala

What a @#$ is chemistry??

I really don't know much about the subject, but I think it is involved in all the things that surround us, form the little pieces of salt to the feeling of love, that's why I think it is so important the study of chemistry.
I will be uploading many post about the subject because is a homework and I need good grades, I hope you enjoy them, or just read them. xD
Rola's Stones