C1 Atomic Structure and the periodic table Flashcards
What is the radius of an atom?
About 0.1 manometers (nm)
What is the radius of a nucleus?
Less than 1/10,000 of the radius of an atom
What is the relative mass of a proton and neutron and electron?
Proton = 1
neutron = 1
electron = nearly 0 (very small)
How did scientists initially classify elements on the periodic table?
They arrange them in order of their atomic weight (which is now called relative atomic mass)
What are two problems with the early periodic table?
They were incomplete (since many elements were unknown)
Some elements were also placed in groups with elements that didn’t have similar properties
How did Mendeleev overcome the problems with the early periodic table?
He added gaps for undiscovered elements
He showed that elements with similar chemical properties lined up in groups (however, from their atomic weight, some pairs of elements next each other in the wrong order)
What type of ions do non metals form?
Negative ions
What is the trend in boiling point going down group 0?
As you go down group 0, the boiling point increases
What is the mnemonic about the history of the atom? and who are they?
Don’t ———— Dalton
Tell —————Thomson
Rutherford ——Rutherford
Bohr ————Bohr
Cheated ———Chadwick
What did John Dalton discover?
(He thought that) elements are made from solid spheres
What did JJ Thomson discover?
He discovered that atoms contain negative particles call electrons.
He came up with the plum pudding model
->which is a ball of positive charge with negative electrons embedded into it
What did Ernest Rutherford discover?
He discovered that atoms have a positive nucleus
which he discovers through the gold foil experiment.
His model of an atom was called the nuclear model and had a nucleus and electrons but the electrons weren’t in shells (and there were no neutrons)
What did Niels Bohr discover?
The electrons orbit the nucleus in fix shells
and almost the atomic model that we have today (except no neutrons)
What did James Chadwick discover?
The nucleus also contains neutrons
