Atomic Structure Flashcards
State the models of the atomic structure.
1) Plum pudding (water melon) model of JJ thompson.
2) nuclear atom model of Ernest Rutherford.
3) Planetary atom model of Neil Bohr.
4) Wave mechanics model of Erwin Shrodinger.
What two things did Democritus suggest that the world was made up of?
1)Empty space
2)Tiny particles, which he called “atoms”.
In which year did Democritus make his two things proposal?
Around 400BC
Who was Democritus?
A Greek Philosopher.
What was Democritus’ thoughts on atoms?
He considered atoms to be the smallest particles of matter.
After Democritus’ deduction, what did Aristotle propose/
Aristotle proposed that matter was continuous and was not composed of smaller particles (atoms).
What did Aristotle name the “continuous substance”?
“Hyle”
What did John Dalton do/
He made logical deductions about the nature of the atom, and he made proposals on his deductions.
What did John Dalton do/
He made logical deductions about the nature of the atom, and he made proposals on his deductions.
Were John Dalton’s proposals accepted?
Yes. His proposals were accepted as ‘Dalton’s Atomic Theory’’.
Were John Dalton’s proposals accepted?
Yes. His proposals were accepted as ‘Dalton’s Atomic Theory’’.
What were Dalton’s proposals based on/
His proposals were based on the experimental work of Joseph Proust and Antoine Lavoisier
What did Joseph Proust and Antoine Lavoisier each work on/
Joseph Proust worked on “Law of definite proportion”
Antoine Lavoisier came out with “Law of Conservation Of Mass”
State Dalton’s Atomic theory.
1) Each element is made up of unique type of atoms which are indivisible.
2) Atoms can neither be created nor destroyed.
3) Atoms of the same elements are identical: they have identical mass and show the same physical and chemical properties.
4) when elements combine to form elements, their atoms join in their fixed proportions.
State Dalton’s 1st wrong postulate.
1) Invisibility of atoms: it is now accepted that atoms are made up of subatomic particles (protons, neutrons and electrons etc.)
State Dalton’s 1st wrong postulate.
1) Invisibility of atoms: it is now accepted that atoms are made up of subatomic particles (protons, neutrons and electrons etc.)
State Dalton’s 2nd wrong postulate
2) Impossibility of creating or destroying atoms: in Chemical reactions, atoms cannot be created or destroyed but in Nuclear reactions atoms can be transformed into other atoms (i.e created or destroyed).
*Through radioactivity, new atoms can be formed.
*New elements can be synthesized through fusion reactions ( a type of nuclear reaction)
State Dalton’s 3rd wrong postulate
3) atoms of same element having identical mass: Isotopy (occurrence of isotopes) have shown that atoms of the same element can have different masses. Eg; there are three isotopes of hydrogen (i.e protium, deuterium and tritium)
*Isotopes of the same element will have the same chemical properties (same atomic number) but they’ll have slightly different physical properties (different mass numbers).
Explain Thompson’s plum pudding model.
According to this model, the positive charges of an atom are uniformly distributed in a sphere, and the electrons are also embedded in the sphere in such a way that the attraction of the electrons to the positive charges are just enough to overcome the repulsion among the electrons.
Did JJ Thompson know the positive charges to be protons at the time of his experiment(1897) or at the time of proposing his model(1904)?
No. He did not know them to be protons so he just called them positive charges.
Protons were later discovered by Rutherford in 1919.
Did JJ Thompson know electrons at the time of his experiment(1897) or at the time of proposing his model(1904)?
Yes. He discovered the electrons as negative charges at the time of his experiment in 1897, and he called them “corpuscles”
It was alter later named “electrons” by other scientists.
Did JJ Thompson know electrons at the time of his experiment(1897) or at the time of proposing his model(1904)?
Yes. He discovered the electrons as negative charges at the time of his experiment in 1897, and he called them “corpuscles”
It was alter later named “electrons” by other scientists.
Did Thompson’s model of an atom have a nucleus?
No.
Did Thompson’s model of an atom have a nucleus?
No.
