Atomic structure and periodic table Flashcards
What is an atom?
The smallest part of an element that makes up all matter
What charges do protons, neutrons and electrons have?
protons= +1
electrons= -1
neutrons= 0
What is another name for the shell?
energy levels
What is an element?
a substance made of only atoms with the same number of protons
What is a diatomic molecule/ element?
An element where atoms form molecules of 2 of the same atom bonded together
Name some examples of diatomic elements
Iodine
Bromine
Chlorine
Fluorine
Oxygen
Nitrogen
Hydrogen
I Bring Clay For Our New House
(all group 7 are diatomic)
Wil changing an atom’s number of proton change the atom?
Yes, protons give atoms it’s identity
What is a compound?
A substance made of at least 2 different elements chemically bonded together
What does the atomic number represent?
Protons (same as electrons)
How do you find out number of neutrons?
Mass number- atomic number
What is the definition of an isotope?
Atoms of the same element with the same number of protons but different numbers of neutrons
What is relative atomic mass?
Average mass of an atom taking into account the different masses of the isotopes
How do you work out relative atomic mass?
sum of (isotope abundance x isotope mass number) / sum of abundance
What did Democritus discover about matter?
All matter were made of small lumps called atoms
What did Dalton discover about the atom?
Atoms were indivisible, miniscule spheres that made up all matter
What did Thomson discover about the atom
Discovered electrons. Created plum pudding model. Electrons could be removed.
What was Rutherford’s experiment and what did it prove?
Alpha particles scattering experiment
Fired alpha particles at a sheet of gold foil
Proved:
1) atoms are made of mainly empty space
2) the nucleus has a positive charge
3) nucleus is concentrated at the centre
and around this are the electrons
How did Dmitri Mendeleev improv ethe periodic table?
Left gaps for undiscovered elements.
Mostly put elements in order of relative atomic mass but switched some around.
These allowed for elements with similar properties to line up in columns.
Do metals form positive or negative ions? What about non-metals?
metals= positive
non-metals= negative
How was the periodic table arranged before Mendeleev?
In order of relative atomic mass
What does the group number show?
number of electrons in outer shell
What does the period number show?
number of energy levels (shells)
Describe trends in melting and boiling points of group 1?
As you go down group one, melting and boiling point decreases
Describe trends in reactivity of group 1?
As you go down group 1, reactivity increases
What does an alkali+ water produce?
metal hydroxide+ hydrogen
Describe trends in melting and boiling point of group 7?
As you go down group one, melting and boiling point increases