Atomic Structure and The Periodic Table Flashcards
What does the atomic number tell you?
The number of protons in an atom.
What does the mass number tell you?
The total number of protons and neutrons in the atom.
What are isotopes?
Isotopes are different forms of the same element, which have the same number of protons but a different number of neutrons.
What is the equation for relative atomic mass?
RAM = Sum of (isotope abundance x isotope mass number) ÷ sum of abundances of all the isotopes
Describe the ‘plum pudding model’
Atom shown as a ball of positive charge with electrons stuck in it.
What happened during the alpha particle scattering experiment conducted by Ernest Rutherford and what discoveries were made.
Most particles went through the gold sheet, but some were deflected more than expected at the time, and a small number were deflected backwards.
Rutherford, with his evidence, came up with the nuclear model of the atom. In this, there’s a tiny positively charged nucleus at the centre, where most of the mass is concentrated. A ‘cloud’ of negative electrons surrounds this nucleus - so most of the atom is empty space.
What did Niels Bohr discover?
Bohr proposed that electrons orbit the nucleus in fixed shells and aren’t anywhere in between. Each shell is a fixed distance from the nucleus.
What did James Chadwick discover?
The existence of neutrons in the nucleus.
Describe The Table of Elements made by Dmitri Mendeleev
50 known elements arranged in order of atomic mass but some were switched depending on their properties. Gaps were left in the table to make sure that elements with similar properties stayed in the same groups and to leave room for undiscovered elements.
State the physical properties of metals
Strong (hard to break), but are malleable, good conductors of heat and electricity, high melting and boiling points.
State the physical properties of non-metals
Dull-looking, more brittle than metals, aren’t always solid at room temperature, don’t generally conduct electricity and often have a lower density.
State some properties of transition metals
Transition metals can have more than one ion/charge. They are often coloured and so compounds that contain them are colourful. Transition metal compounds often make good catalysts.
Describe the trends for the alkali (Group 1) metals as you go down the group
Increasing reactivity, lower melting and boiling points and higher relative atomic mass.
State the properties of Group 1 metals.
More reactive than transition metals. Much less dense, strong and hard than transition metals and have much lower melting and boiling points.
Describe the trends as you go down Group 7 (halogens)
The halogens become less reactive, have higher melting and boiling points, higher relative atomic masses.
