The Atom Flashcards
What is a atom
Smallest part of an element that can exist
What is daltons model of the atom
Atoms are solid spheres that could not be divided into smaller parts
What is the plum pudding model of the atom
Sphere of positive charge with negative electrons embedded in it
What did scientist discover in the alpha scattering experiment
Some alpha particles were deflected by the gold foil. This showed that an atoms mass and positive charge must be concentrated in one small space
Describe the nuclear model of the atom
Dense nucleus with electrons orbiting it
What did Niels Bohr discover
Electrons orbit in fixed energy levels (shells)
What did James Chadwick discover
Uncharged particle called the neutron
Where are protons and neutrons
In the nucleus
What is the relative mass of each subatomic particle
Proton 1
Neutrons 1
Electron 0
What is the relative charge of each sub atomic particle
Proton +1
Neutron 0
Electron -1
How can you find out the number of protons in an atom
The atomic number on the periodic table
How can you calculate the number of neutrons in an atom
Mass number - atomic number
Why do atoms have no overall charge
They have equal numbers of positive protons and negative electrons
How many electrons would you place in the first, seconds and third shells
Up to 2 in the first shell and up to 8 in the second and third shells
What is an element
Substance made of one type of atom
What is a compound
Substance made of more than one type of atom chemically joined together
What is a mixture
Two or more substances not chemically combined
What are isotopes
Atoms of the same element
What are the five physical processes that can be used to separate mixtures
Filtration
Crystallization
Distillation
Fractional distillation
Chromatography
What is relative mass
The average mass of all the atoms of an element
Give a reason why an original line is drawn in pencil in a chromatography practical
Pencil doesn’t interact with the mobile phase, and therefore will not interfere with the chromatogram
A particle has 4 protons and 4 electron
Give the charge on the particle
0
A particle has 5 protons and 4 electrons
Determine whether the particle is an atom or an ion
Ion
What is an ion
An atom or molecule that has either gained or lost an electrons giving it a positive or negative charge
Isotopes are atoms of an element that have the same number of ——- but different number of ——
Protons
Neutrons
The chemical symbol for silicon is 28,14 Si
Describe an atom of silicon in terms of the number of protons, neutrons and electrons and their charges
14 positive protons
14 neutral neutrons
14 negative electrons
Describe the alpha particle model scattering experiment and how it showed that the mass of an atom was concentrated in a positevly charged nucleus
Alpha particles were fired at a sheet of gold foil
Most passed through the foil
So most of the atom is empty space
Small number bounced back
So that must of collided with something
A small number passed through but was deflected
Positively charged alpha particles passed near possitevly charged nucleus and were repelled
Neutrons we’re not shown to be in the nucleus until 20 years after the nuclear model was accepted. Suggest a reason why it took so long to prove that neutrons existed
Have no charge
Use your own knowledge to compare the plum pudding and nuclear model
Both have electrons
Both have positive parts
Plum pudding has electrons all over the place whereas nuclear has electrons in shells
Plum pudding is all positive whereas nuclear has a positive centre
Nuclear model has a nucleus whereas plum pudding dosent
Nuclear model shows electrons with different energy levels
Identify the three elements in H2SO4 use the periodic table to help you
Hydrogen
Oxygen
Sulfur
Explain why the relative atomic mass of copper, Cu, is not a whole number
Copper has multiple isotopes
Write the chemical formula for sodium and chlorine
NaCl
