What are the chemical symbols of some common elements?
H (Hydrogen), O (Oxygen), C (Carbon), N (Nitrogen), Fe (Iron), Au (Gold)
how did Mendeleev arrange the elements into the periodic table?
In order of increasing relative atomic mass and put those with similar properties below each other into groups and left gaps for yet to be discovered elements and switched the order of a few elements to keep the groups consistent.
How did Mendeleev predict the existence and properties of some elements yet to be discovered?
By looking at the chemical properties and physical properties of the elements next to a gap, he could also predict the properties of these undiscovered elements.
how were meant to leave early ideas supported by later evidence?
When the undiscovered elements he had left gaps for were found they fitted the pattern.
what were the problems Mendeleev had when he was ordering the elements?
Sam elements did not fit into the order of increasing relative atomic mass, so some pairs had to be reversed. For example, Iodine has a lower relative atomic mass than tellurium. So should be placed before tellurium but it has similar chemical properties to chlorine and bromine. So Mendeleev swapped the positions of iodine and tellurium.
how are elements arranged in the modern periodic table?
rows, called periods, in order of increasing atomic number
vertical columns, called groups, where the elements have similar properties
where are metals and non-metals positioned in the periodic table?
Metals are on the left side of the periodic table, while non-metals are on the right side.
what is an electron configuration?
The arrangement of electrons in an atom or molecule.
How are electron configurations shown on diagrams?
2 electrons occupy the first shell
8 electrons occupy the second shell
1 electron occupies the third shell
what is the link between an elements position in the periodic table and its electron configuration?
the number of shells is the period number
the number of electrons in the outermost shell of an element is the group number
the number of electrons in all shells of an element is the element's atomic number