Atomic Structure (Chemistry) Flashcards
What did Neils Bohr discover?
That electrons orbited the nucleus at specific distances, called shells
What subatomic particles have no charge?
Neutrons
What number tells us how many protons there are in an atom?
The atomic number
What subatomic particles have a charge of +1?
Protons
The discovery of what lead to scientists not accepting the Dalton model of the atom anymore?
Electrons, as they were smaller than the atom.
What is the smallest part of an element that can exist?
An atom
Why do scientists know that the Dalton model of the atom isn’t correct?
Other scientists have done many experiments to show the Dalton Model doesn’t fit
What does the mass number tell us about the atom?
The number of protons PLUS the number of neutrons.
What word means the same as electron shell?
energy level
How many different elements are there?
About 100
What is the relative mass of an electron?
0
How are compounds formed?
From chemical reactions where bonds are broken and then reformed.
What is a substance made of only one type of atom?
An element
What are the 3 forms that substances can exist in?
Elements Compounds Mixtures
What did James Chadwick discover?
The neutrons in the nucleus
What can never be the same for 2 different elements?
The atomic number, or the number of protons.
What is the plum pudding model of the atom?
A ball of positive charge with negative electrons studded into it.
How many letters are there in a chemical symbol?
One or two depending on the element.
What is the charge of an electron?
negative 1 (-1)
What subatomic particles have a charge of -1?
Electrons
What experiment disproved the plum pudding model?
The gold foil experiment
What model became accepted after the gold foil experiment?
The nuclear model
What was the first model of the atom called?
The Dalton Model
What is the charge of a proton?
positive 1 (+1)
Name the 3 subatomic particles.
Protons, neutrons and electrons
What are all substances made from?
Atoms
Does separating a mixture involve a chemical reaction? Explain.
No, it doesn’t involve a chemical reaction because no chemical bonds are being made or broken.
Who discovered neutrons?
James Chadwick
What does the Dalton Model of the atom look like?
A sphere that can’t be made any smaller
Why are atoms neutral?
They have the same number of protons as electrons.
What is the charge of a neutron?
Neutral or No Charge
Which subatomic particle can tell us the identity of an atom?
The number of protons
What is involved in a chemical reaction?
The formation of one or more new substances and an energy change.
What came after the discovery of electron shells?
The discovery of protons, that the nucleus wasn’t one big positive charge, but many smaller posive charges.
What did the gold foil experiment (alpha particle scattering) prove?
That atoms have nucleuses with a positive charge.
What is the relative mass of a proton?
1
What is an atom?
The smallest part of an element that can exist.
What is a mixture
A substance made of more than one thing not chemically bonded together.
How many electrons can fit in the first shell?
2
Where do we find all the different elements?
On the periodic table.
What is the relative mass of a neutron?
1
How many electrons can fit in the 3rd shell?
8
What is an element?
A substance made of only one type of atom.
How many electrons can fit in the second energy level?
8
How do we figure out how many neutrons there are in an atom?
Mass number - atomic number
Who discovered electron shells?
Neils Bohr
What is a molecule?
A substance made of more than one atom chemically bonded together.
What are the 2 numbers you see on the periodic table for each element?
The atomic number (smaller) and the mass number (bigger)
What does the atomic number tell us about the atom?
The number of protons in the atom
What is a substance made from two or more different atoms chemically bonded together?
A compound.
What subatomic particles have a neutral charge?
Neutrons
What subatomic particles have a relative mass of 1? (2)
Protons and Neutrons
How can mixtures be separated? (5)
Filtration, crystallization, simple distillation, fractional distillation, chromatography
What was the name of the model which explained electrons embedded in a positive atom?
The plum pudding model
What sub atomic particle has no relative mass?
An electron
What is a compound?
A substance made of two or more different atoms chemically bonded together.
