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C1 C) Drawing Atoms
C1 C) Drawing Atoms
The periodic table also gives us the atomic number and mass number of elements. An example of an element tile for boron is shown below.
The atomic number tells us how many protons an element has, and it is written below the letter symbol. The atomic number for boron is 5, so boron will have 5 protons.
Elements are neutrally charged, which means that an element will have the same number of protons as electrons (remember, protons and electrons have the same magnitude of charge, but in opposite directions; protons have a charge of +1 and electrons have a charge of -1). This means that the atomic number for an element is the number of electrons as well as the number of protons. So, the atomic number for boron is 5, which means that boron will have 5 electrons (as well as 5 protons).
The mass number tells us the total number of protons and neutrons in an element. The mass number is written above the letter symbol. Boron has a mass number of 11; the number of protons and neutrons in boron is 11. The atomic number gives us the number of protons, so we can work out the number of neutrons in an element by taking the atomic number (number of protons/ bottom number) away from the mass number (top number). For boron, we take 5 away from 11, which gives us 6 (11 – 5 = 6). Therefore, boron has 6 neutrons.
So, we have found that boron has 5 protons, 6 neutrons and 5 electrons.
Elements are neutrally charged, which means that an element will have the same number of protons as electrons (remember, protons and electrons have the same magnitude of charge, but in opposite directions; protons have a charge of +1 and electrons have a charge of -1). This means that the atomic number for an element is the number of electrons as well as the number of protons. So, the atomic number for boron is 5, which means that boron will have 5 electrons (as well as 5 protons).
The mass number tells us the total number of protons and neutrons in an element. The mass number is written above the letter symbol. Boron has a mass number of 11; the number of protons and neutrons in boron is 11. The atomic number gives us the number of protons, so we can work out the number of neutrons in an element by taking the atomic number (number of protons/ bottom number) away from the mass number (top number). For boron, we take 5 away from 11, which gives us 6 (11 – 5 = 6). Therefore, boron has 6 neutrons.
So, we have found that boron has 5 protons, 6 neutrons and 5 electrons.
We can now draw what boron looks like. The 5 protons and 6 neutrons for boron will be in the nucleus of the atom. We now move onto looking at the electrons. Electrons will always fill the shell that is the closest to the nucleus of an atom and each of the electron shells only takes a certain number of electrons. The first shell can only take a maximum of 2 electrons, and the second and third shells can take a maximum of 8 electrons. Boron has 5 electrons; 2 of the electrons will be in the first shell (the first shell can only take 2), and the remaining 3 electrons will be in the second shell. The electron structure will be 2, 3. The diagram for boron is shown below.
In the periodic table section, we learnt that the periods refers to the number of electron shells that are in use and the groups refers to the number of electrons that are in their outermost shell. When we find boron in the periodic table, we see that it is in period 2, so it should have 2 electron shells in use (which it does), and it is in group 3, so it should have 3 electrons in its outermost shell (which it also does).
Fluorine
We are now going to draw fluorine. Fluorine’s tile in the periodic table is shown below.
We are now going to draw fluorine. Fluorine’s tile in the periodic table is shown below.
The atomic number for fluorine is 9, and this means that it has 9 protons. Elements are neutrally charged, which means that the number of protons will be equal to the number of electrons. Therefore, as there are 9 protons in fluorine, there will also be 9 electrons. We work out the number of neutrons by taking the atomic number (9) away from the mass number (the top number, which is 19 for fluorine). This tells us that fluorine has 10 neutrons (mass number – atomic number; 19 – 9 = 10). Therefore, fluorine has 9 protons, 10 neutrons and 9 electrons.
The 9 protons and 10 neutrons for fluorine will be in the nucleus of the atom (the centre). Usually when we draw an element/ atom, we don’t draw all of the protons and neutrons in the nucleus as our diagram will look messy. Instead we just represent the nucleus as a dot or as the letter of the element (this is shown on the sketch below).
The 9 electrons will be in the electron shells that surround the nucleus. The electrons fill the shells that are closest to the nucleus of the atom. The first shell can only take a maximum of 2 electrons, and the second and third shells can take a maximum of 8 electrons. Fluorine has 9 electrons; 2 of the electrons will be in the first shell, and the remaining 7 electrons will be in the second shell. The electron structure will be 2, 7. The diagram for fluorine is shown below.
The 9 electrons will be in the electron shells that surround the nucleus. The electrons fill the shells that are closest to the nucleus of the atom. The first shell can only take a maximum of 2 electrons, and the second and third shells can take a maximum of 8 electrons. Fluorine has 9 electrons; 2 of the electrons will be in the first shell, and the remaining 7 electrons will be in the second shell. The electron structure will be 2, 7. The diagram for fluorine is shown below.
Let’s now look at the period and group for fluorine in the periodic table. When we find fluorine in the periodic table, we see that it is in period 2, so it should have 2 electron shells in use (which it does), and it is in group 7, so it should have 7 electrons in its outermost shell (which it also does).
Potassium
We are now going to draw potassium. Potassium’s tile in the periodic table is shown below.
We are now going to draw potassium. Potassium’s tile in the periodic table is shown below.
The atomic number (bottom number) tells us the number of protons that potassium has; potassium has 19 protons. All elements are neutrally charged, which means that the number of protons will be equal to the number of electrons; therefore, potassium has 19 electrons. We work out the number of neutrons by taking the atomic number (19) away from the mass number (39); this tells us that potassium has 20 neutrons (19 – 19 = 20).
We are now going to draw potassium. The 19 protons and 20 neutrons will be in the nucleus of the atom. Like the example before, I will represent the nucleus of the atom with the letter of the element.
The 19 electrons will be in the electron shells filling the shells that are closest to the nucleus first. The first shell takes 2 electrons, the second and third shells take 8 electrons. As potassium has 19 electrons, it will have 2 in the first, 8 in the second, 8 in the third and 1 in the fourth (2 + 8 + 8 + 1 = 19).
A sketch for potassium is shown below.
The 19 electrons will be in the electron shells filling the shells that are closest to the nucleus first. The first shell takes 2 electrons, the second and third shells take 8 electrons. As potassium has 19 electrons, it will have 2 in the first, 8 in the second, 8 in the third and 1 in the fourth (2 + 8 + 8 + 1 = 19).
A sketch for potassium is shown below.
On our diagram, potassium has 4 electron shells and 1 electron in its outermost shell. We know that the number of electron shells is the period number; this means that potassium will be in period 4. Also, the number of electrons in an element’s outermost shell is the group number; this means that potassium will be in group 1. When we find potassium in the periodic table, we see that it is in period 4 and in group 1.