C4 Flashcards
Which scientist proposed the theory that all atoms of the same elements were the same?
John Dalton in the 1800s
Which scientist discovered the electron?
J.J Thompson in the 1890s
Which scientist discovered that the atom had a dense area called the nucleus?
Ernest Rutherford in 1911
Which scientist predicted that electrons occupy orbitals?
Niels Bohr in 1913
What is in the centre of an atom and what is it surrounded by?
The nucleus and it’s surrounded by negatively charged electrons
What is the nucleus made up of?
Protons and neutrons
What charge does the the nucleus have?
It is positively charged but the atom has no overall charge
Why does the atom have no overall charge?
It has the same number of positive protons and negative electrons. So the charges cancel eachother out.
What is an element?
One type of atom. Elements can’t be chemically broken down. There are just over 100 naturally occurring elements.
What is a compound?
A compound is a substance made of two or more elements that are chemically combined.
What is the mass number and what makes it up?
The mass number is the top number (above the element symbol) and it is made up of the total number of protons and neutrons in an atom
What is the atomic number and what makes it up?
The atomic number is the bottom number (below the element symbol) and is made up of the number of protons in an atom
How are the elements in the periodic table arranged?
In increasing atomic number
How is the group number worked out?
The same as the number of the electrons in the outer shell of an elements atom.
How can the period number be worked out?
The same as the number of occupied shells
What are isotopes
Atoms of the same element that have the same atomic number but different mass number
What is electron configuration?
How the electrons are arranged around the nucleus in shells (energy levels)
How many electrons can the first second and third shell hold?
The first shell = 2
The second shell = 8
The third shell = 8
What is an ion?
A charged atom or group of atoms
What is a positive ion?
When an atom or a group of atoms lose 1 or more electrons
What happens to the non-metal atom during ionic bonding?
It gains electrons to fill its outer shell and become a negative ion
What happened to the metal atom during ionic bonding?
It loses all outer shell electrons to become a positive ion
What is an ionic bond?
When the positive and negative ions are attracted to eachother
What are ionic lattices?
When positive and negative ions are strongly attracted to eachother
Name 2 compounds that form giant ionic lattices?
Sodium chloride and Magnesium oxide
Why do ionic lattices have high melting points?
There is a strong attraction between oppositely charged ions
How comes ionic lattices can conduct electricity in molten or in solution?
The charged ions are free to move about
How comes ionic lattices can’t conduct electricity when solid?
The ions are held in place and cannot move
Does Magnesium oxide or Sodium chloride have a higher melting point?
Magnesium oxide as the ionic bonds are stronger and need more energy to be broken
What happens when a metal and non-metal combine?
Electrons are transferred from one atom to the other forming ions. Each ion will have a complete outer shell (a stable octet)
