Atomic Structure Flashcards
Give some facts on the nucleus.
Its in the middle of the atom
It contains protons and neutrons
It has a positive charge because of the protons
Almost the whole mass of the atom is concentrated in the nucleus
Give some facts on the electrons.
They move around the nucleus in electron shells
They are negatively charged and tiny, but they cover a lot of space
The volume of their orbits determines the size of the atom
Electrons have virtually no mass
What are the particles relative mass and charge?
Particle. Relative Mass. Charge
Proton. 1. +1
Neutron. 1. 0
Electron. Very small. -1
What is the charge of an atom and why?
They are neutral because they have the same number of protons as electrons so they cancel out.
What does a nuclear symbol tell you?
An atoms atomic (proton) number and mass number.
What is the atomic number?
Tells you how many protons there are.
What is the mass number?
Tells you the total number of protons and neutrons in the atom.
How do you get the number of neutrons?
Just subtract the atomic number from the mass number.
What is an element?
A substance made up of atoms that all have the same number of protons in their nucleus.
What is a compound?
Different types of atoms bonded together.
What was the first idea of atoms?
At the start of the 19th century, John Dalton described atoms as solid spheres and said that different spheres made up the different elements.
What was the second idea on atoms?
In 1897, JJ Thomson came up with the plum pudding model. This had electrons in as bit of the plum pudding and positively charged particles as the pudding.
What was the third idea about atoms?
In 1909, Ernest Rutherford and his student Ernest Marsden conducted the famous alpha particle scattering experiment. They found that the mass is concentrated at the centre, the nucleus is charged and most mass is in the nucleus and the atom is mostly empty space. The electrons were in a cloud around the nucleus. They contain positively charged particles called protons.
What was the fourth idea about atoms?
In 1914, Neil Bohr found that electrons are in fixed shells and orbit the nucleus and each shell is a set distance from the nucleus.
What was the fith idea about atoms?
In 1932, James Chadwick discovered that there are nuetrons in the nucleus.
Electron shell facts.
The shells are filled with atoms in 2882 pattern
They are much happier when they have full electron shells
In most atoms the outer shell is not full and this makes the atom want to react to fill it.
Hwo do you work out the electronic structure?
The atomic number is the number of electrons.
So it has to fit into 2,8,8,2
What is ion?
Charged particles.
What are the groups that most readily form ions?
Groups 1,2,6,7
What is an isotope?
Atoms of the same element with different number of neutrons.
What are some features of isotopes?
They have the same atomic number but different mass numbers
Extra neutrons could make the nucleus unstable so it is radioactive.
Atoms of the same element that have different masses.
They will have different physical properties such as density and maybe radioactiveness.
They will always have the same chemical properties because that depends on the elctronic structure and they all have the same number of electrons.
What is ionic bonding and what is covalent bonding?
Ionic - transferring electrons
Covalent - sharing electrons
