Atomic structure and periodic table Flashcards
What was john daltons theory on the atom
He thought that all matter was made of tiny
particles called atoms, which he imagined as tiny solid balls. Dalton’s model included these ideas:
atoms cannot be broken down into anything simpler
the atoms of a given element are identical to each other
the atoms of different elements are different from one another
- Thomson’s Plum Pudding Model (1897):
J.J. Thomson’s discovery of electrons led him to propose the “plum pudding” model, where negatively charged electrons were embedded in a positively charged sphere.
- Rutherford’s Nuclear Model (1911):
Ernest Rutherford’s gold foil experiment revealed that the atom’s positive charge was concentrated in a small, dense core called the nucleus, surrounded by electrons.
- Bohr’s Planetary Model (1913):
Niels Bohr proposed that electrons orbited the nucleus in specific energy levels or shells, resolving the instability of the Rutherford mode
Describe isotopes as
different atoms of the same element containing the same number of protons but different numbers of neutrons in their nuclei
How do we find the relative atomic mass with the isotopes and different abundances
You add all of the (relative isotopic masses * abundance) together and divide all of that by 100
Describe how Mendeleev arranged the elements, known at that time, in a periodic table by using properties of these elements and their compounds.
Ordered them in order of increasing atomic mass but also taking into account the similar chemical properties for each column
Mendeleev also left gaps in the table for undiscovered elements and predicted their properties based on the surrounding elements.
Explain that Mendeleev thought he had arranged elements in order of increase relative atomic mass but this was not always true because
of the relative abundance of isotopes of some pairs of elements in the periodic table
Describe that in the periodic table
Elements are arranged in order of _____ _______ _______, in rows called periods
Elements with ______ ________ are placed in the same vertical columns called groups
increasing atomic number
similar properties
How do you distinguish between non metals and metals on a periodic table
A staircase going down from boron
Explain how the electron configuration of an element is relative to its position in the periodic table.
The number of electron shells correspond to the period number of the element
