Atoms Flashcards
What is an atom?
The defining structure of an element
How are atoms structured?
A nucleus made up of protons and neutrons, which is orbited by electrons.
What does the number of protons in an atom tell you?
The number of protons tells you what kind of atom it is.
What is the nucleus made up of?
Positively-charged protons and uncharged neutrons.
How do electrons act?
Electrons orbit the nucleus in a nice orderly fashion, electrons stay within a certain electron ‘shell’.
How do electrons and protons interact?
Negatively-charged electrons are attracted tō positively-charged protons (electrostatic attraction).
Explain electrostatic attraction.
Electrostatic attraction is the attractive forces holding atoms together. It allows them to exist in compact structures.
How do electrons orbit?
Electrons orbit in specific rings called ‘electron shells’. All the electrons stick to their own path as they travel around the nucleus.
How many electrons can each shell hold?
The first shell holds 2, the second and third shells hold up to 8 electrons.
How many protons and electrons are there in an atom?
In a normal atom there are equal numbers of protons and electrons.
Why are atoms neutral?
They have the same amount of positive and negative charges.
How many protons and neutrons does Nitrogen have?
Nitrogen is number 7 in the periodic table so it has 7 protons and 7 electrons.
How do electrons fit into an atom?
They start by filling up the first electron shell, and when that’s full they’ll fill up the second electron shell, and so on.
What is an electron shell?
An electron shell is an organised group of electrons orbiting the nucleus.
Do all atoms have the same amount of electron shells and electrons?
No, different atoms have different numbers of electron shells and electrons within in each shell.
What is the electron configuration?
The number of electrons in each shell.
How many protons, neutrons and electrons does Carbon have?
6 protons, 6 neutrons and 6 electrons.
What is the electron configuration of Carbon?
(2,4)
How many protons, neutrons and electrons does Sodium have?
11 protons, 11 neutrons and 11 electrons.
What is the electron configuration of Sodium (Na)?
(2,8,1)
What is the electron configuration for Oxygen (O)?
(2,4)
What is a chemical symbol?
A shortened version of the name for each element.
What is the atomic number?
It tells you what the number of protons is. It is found in the top left corner of each square in the periodic table.
What is the mass number?
It tells you how many particles are in the nucleus. This protons + neutrons.
How can you work out the number of neutrons?
Neutrons = mass number - atomic number.
What are the rows in a periodic table called?
Periods
What are the columns in periodic tables called?
Groups
How can you use the periods in a periodic table to work out the number of electron shells?
By counting the number of periods, you can work out the number of electron shells the atoms have. All the atoms in the second period have 2 electron shells.
How can you use the groups in a periodic table to work out the number of electrons in the outer shell?
By counting the groups, you can work out the number of electrons in the very outer shell. All the atoms in Group 1 have 1 electron in their last shell.
What is the trick for the elements in Groups 13-18 of the periodic table?
Remember to minus the 10 from the group number to get the valence number.
What is a valence electron?
Valence electrons are electrons in the outermost shell of an atom.
Calculate the number of protons, neutrons and electrons Lithium has?
P = 3
N = 4 (mass - atomic number, 7 - 3 = 4)
E = 3 ( P=E)
Calculate the number of protons, neutrons and electrons Fluorine (F) has?
P = 9
N = 10 (19 - 9)
E = 9
Calculate the number of protons, neutrons and electrons Magnesium (Mg) has?
P = 12
N = 12 (24 - 12)
E = 12
How do you calculate the number of protons an element has using its atomic number?
The number of protons in an atom is equal to the atomic number of the element.
How do you calculate the number of electrons and neutrons an element has, using its atomic and mass numbers?
Number of electrons = atomic number.
Number of neutrons = mass number - atomic number.
How many electrons are in the first three shells of an atom?
2, 8, 8
Draw an atom, and label the key structural components of it.
Nucleus made up of protons and neutrons surrounded by electron shells.
