1 Atomic Structure - Atomic Model Flashcards
Define atom
The smallest part of an element that can still be recognised as that element
Define element
A substance made of only one type of atom
Define compound
A substance made of two or more different atoms chemically bonded together
Define molecule
A substance made of more than one atom chemically bonded together (can be atoms of the same type!)
Define mixture
A substance made of more than one thing not chemically bonded together
State the three subatomic particles
Protons, neutrons, electrons
State the masses of the subatomic particles
Protons: 1, neutrons: 1, electrons: 0
State the relative charges of the subatomic particles
Protons: +1, neutrons: 0, electrons: -1
How are the subatomic particles arranged in an atom? (3 marks)
Protons and neutrons in the nucleus, electrons orbiting in shells
What is the plum pudding model of the atom?
A ball of positive charge with negative electrons studded into it
What did the gold foil (Rutherford Scattering) experiment prove?
That atoms have dense nucleuses with a positive charge
What is the atomic number of an atom?
The number of protons in an atom
What is the mass number of an atom?
The number of protons + the number of neutrons in an atom
How do you calculate the number of neutrons in an atom?
Mass number - atomic number
How are the electrons arranged in atoms?
Orbiting the nucleus in shells
How many electrons can go in the first shell?
2
How many electrons can go in the second and third shells?
8
What is an ion?
an atom which has lost or gained electron(s)
What are all substances made of?
Atoms
What is an isotope?
An atom of the same element with a different number of neutrons.
Where are neutrons found?
In the nucleus
Where are protons found?
In the nucleus
Where are electrons found?
Orbiting the nucleus in shells
If an element has an atomic number of 6, what does this tell you about the atom?
There are 6 protons in the nucleus
An element has a mass number of 23 and a mass number of 11. How many protons are there? How many neutrons are there?
11 protons, 12 neutons
How does an atom become a positive ion?
loses an electron
How does an atom become a negative ion?
Gains an electron
Who discovered the electron?
J.J. Thomson
The same element must always have the same number of…?
Protons
What is the majority of the mass of an atom?
The nucleus, as the mass of an electron is almost zero compared to the mass of protons and neutrons
What was Dalton’s theory about the atom?
all matter is made of small invisible units called atoms
What was Thomson’s theory about the atom?
He discovered the electron and therefore knew the atom was made up of charged particles. He introduced the Plum Pudding Model
What was Rutherford’s theory about the atom?
following the alpha particle scattering experiment he update the plum pudding model to the Nuclear Model; that most of the mass of the atom was concentrated in the nucleus which carries a positive charge
What was Bohr’s theory about the atom?
Bohr updated the Nuclear model to show that electrons orbit the nucleus in certain energy levels
What was Chadwick’s theory about the atom?
discovered the neutron
Why did the discovery of electrons mean that Dalton’s model of the atom needed to be updated?
That atoms were not the smallest thing anymore, as the electron was smaller than the atom
What is the difference between a mixture and a compound?
In a compound the elements are chemically bonded. They are not chemically bonded in a mixture
How can an atom become and ion with a 2+ charge?
Loses two electrons
Explain the overall charge on an atom.
The overall charge will be neutral as there are the same number of protons (with a positive charge) as electrons (with a negative charge). Making the atom have no overall charge.
What is a reactant?
The substances you start with in a chemical reaction.
What is a product?
The substances made in a chemical reaction.
When is an equation balanced?
When there are the same number of each type of atom on both sides of the equation.
What does the state symbol (s) mean?
The substance is solid
What does the state symbol (l) mean?
The substance is liquid
What does the state symbol (g) mean?
The substance is a gas
What does the state symbol (aq) mean?
The substance is aqueous
What does aqueous mean?
The substance can be dissolved in water.
