Topic 1 Flashcards
What is an isotope
An atom of an element that has the same number of protons but a different number of neutrons
What is the atomic number?
The number of protons
What is the relative atomic mass?
The number of protons+nuetrons
How do you separate a solid from a liquid?
Filtration
How do you separate two liquids from one another?
Fractional distillation
How do you remove a dissolved solid from a liquid (e.g salt dissolved in water)
crystallization
How does crystallization work?
- slowly heat the solution until all the water evaporates
What is a compound?
- two elements
- chemically bonded together
What is the plum pudding model? Draw it
- the whole atom is positive
- there are negative electrons dotted around the atom
What was the alpha particle scattering experiment?
- alpha particles are shot at a sheet of gold foil
- most went straight through and some were deflected
- lead to the nuclear model
What is the nuclear model?
- all the positive charge is held in the center
- all the mass is held in the center
- most of the atom is empty space
Who discovered electron shells?
Bohr
Who discovered neutrons?
Chadwick
What is the charge of a proton?
+1
What is the charge of a neutron?
0
What is the charge of an electron?
-1
What is the mass of a proton?
1
What is the mass of a neutron?
1
What is the mass of an electron?
Almost 0
Why were gaps left in the early periodic table?
- for elements that had not yet been discovered
- Mendeleev believed elements would be discovered that filled the gaps
Why did Mendeleev reorder some elements in the periodic table?
So elements were in groups that had similar chemical properties
Why do elements in the same group have similar chemical properties?
They have the same number of electrons in their outer shell
What elements are diatomic?
- all of group 7
- oxygen
What are the differences between group 1 metals and transition metals? (6points)
- transition metals are harder to
- transition metals are more dense
- transition metals have higher melting points
- transition metals are less reactive
- Transition metals can be used as catalysts
- transition metals can form ions with more than 1 charge
