1.1 Atomic Structure Flashcards
What caused Dalton’s simple model to change over time?
The discovery of subatomic particles
When did Dalton come up with the solid atom model and what was it?
He came up with it in 1803. It stated that all atoms of an element are identical; different elements have different atoms.
Who discovered the electron in 1897?
JJ Thomson
What was JJ Thomson’s atomic model called?
The plum pudding model
What was the plum pudding model of 1904?
Atoms of positive charge with negative electrons dotted around inside
Who came up with the solar system model in 1911?
Ernest Rutherford
What was the solar system model?
Atoms have a positive nucleus surrounded by negative electrons in orbits
What was Niels Bohr’s electron shell model, which he came up with in 1913?
Electrons occupy shells or energy levels around the nucleus
In 1918, who discovered the proton?
Ernest Rutherford
In 1932, who discovered the neutron?
James Chadwick
What is the structure of an atom?
An atom consists of a central nucleus, which contains protons and neutrons and is surrounded by electrons in shells
What is the relative charge and relative mass of a proton?
+1, 1
What is the relative charge and relative mass of a neutron?
0, 1
What is the relative charge and relative mass of an electron?
-1, 1/1836
Why do atoms have an equal number of protons and electrons?
Because the atom’s charge has to be neutral overall
Describe the nucleus of an atom
Very small compared to the overall size of the atom. Most of the mass of an atom is concentrated in the nucleus.
What is the meaning of the term mass number of an atom?
the sum of protons and neutrons
