Topic 1: Atomic Structure Flashcards
What did Robert Boyle propose in 1663?
He proposed that there were some substances that could not be made simpler. These were the chemical elements as we now know them.
What did John Dalton propose in 1803?
He proposed that elements were composed of indivisible atoms. All of the atoms of a particular element had the same mass and atoms of different elements have different masses. Atoms could not be broken down.
What did Henri Becquerel discover in 1896?
He discovered radioactivity. This showed that particles could come from from inside the atom. Therefore the atom was not indivisible.
What did J.J. Thomson discover in 1897?
He discovered the electron. This was the first sub atomic particle to be discovered. He showed that electrons were negatively charged and electrons from all elements are the same.
What realisation was made from J.J. Thomson’s discovery in 1897?
As electrons had a negative charge, there had to be some source of positive charge inside the atom too. Also, as electrons were much lighter than whole atoms, there had to be something to account for the rest of the mass of the atom.
What model of the atom did J.J. Thompson propose?
He suggested that the electrons were located within the atom in circular arrays, like plums in a pudding of positive charge. This is commonly known as the Plum Pudding Model.
What did Ernest Rutherford discover in 1911?
He found that most of the mass and all of the positive charge of the atom was centred in a tiny nucleus.
What are the three fundamental particles?
Protons, Neutrons and Electrons.
What forms the nucleus of an atom?
Protons and Neutrons.
What is the collective term for protons and neutrons?
Nucleons, due to being found in the nucleus.
What is the mass of a proton?
1.673 x 10^-27 kg
What is the mass of a neutron?
1.675 x 10^-27 kg
What is the mass of an electron?
0.911 x 10^-30 kg
What is the actual charge of a proton?
+1.602 x 10^-19 C
What is the charge of a neutron?
0 C
What is the actual charge of an electron?
-1.602 x 10^-19 C
Where is the electron positioned?
Around the nucleus in orbitals/shells.
What is the relative charge of a proton?
+1 C
What is the relative charge of an electron?
-1 C
What is the relative mass of a neutron?
1
What is the relative mass of a proton?
1
What is the relative mass of an electron?
1/1840
What is the name of the force that holds the protons and neutrons together in the nucleus?
Strong Nuclear Force
What is the name of the force holding protons and electrons together?
Electrostatic forces of attraction
Why don’t protons repulse each other in the nucleus?
The Strong Nuclear Force overcomes the repulsion. SNF only acts over very short distances however.
What does the atomic number tell you?
The number of protons in the nucleus, Z.
What is usually equal to the number of protons?
The number of electrons.
What determines the chemical properties of an element, and what element it is?
The number of electrons in the outer shell of an atom?
What does the atomic number of element determine?
The chemical identity of an element.
In the same element, does the atomic number differ or stay the same between every atom?
Stays the same.