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Names and places
You should now be able to answer the following questions
34. What is the centre of the atom/ion called?....................................
35. What is the charge of the proton?.............................................
36. What is the charge of the neutron?...........................................
37. What is the charge of the electron?.............................................
38. Fill in the labels of the picture to the right.
Simulation
With the button to the right, you'll open a simulation. Use it to answer questions 39 to 46.
The elements
In the first part of the simulation (atom), add and remove protons, neutrons and electrons until you find out what it is that determines what element a certain atom is.
39. The rule: The amount of………………………. determines what element a certain atom is.
Test your idea by identifying the element for the 3 examples in the table below.
Because the element is (apparently) determined by an amount, every element has its own unique number. We call this number the atomic number and it is this number that determines the order in which the elements appear on the periodic table of the elements.
Charge
Click on the green + next to “net charge” so the simulation tells you the charge of the atom.
Play around with the simulation until you can complete the following rules about the charge.
Complete the following rules:
40. A neutral atom (no charge) has the same amount of…………………as……..……………
41. A positive ion (positive charge) has more……………………than…………………………
42. A negative ion (negative charge) has more…………………than…………………………
43. So, to calculate the charge you need to: ……………………………………………………………………………
Incidentally, you’ve discovered another rule: When the atom is neutral, it is called an atom but when it has a net charge (positive or negative) it is called an………………….
44. Fill in the table below and after that, check your answers using the simulation.
Mass number
Click on the green + next to “mass number” so the simulation tells you the mass number of the atom.
Add and remove protons, neutrons and electrons and keep an eye on the mass number until you can complete the following rules:
45. The mass number is the amount of ……………………plus the amount of………………………
46. The electrons have ……… effect on the mass number.
Isotopes
As you have noticed, you can change the mass number without changing the element. Atoms of the same element but with a different mass number are called isotopes.
In the case of hydrogen, the different isotopes have been given names: hydrogen with no neutrons is called protium, hydrogen with one neutron is called deuterium. These two hydrogen isotopes exist in nature; 99,9885% of all the hydrogen is protium and 0,0115% is deuterium.
Hydrogen may also have two neutrons but this an artificial atom, made in a nuclear power plant. This atom is called tritium.
47. Let’s practise, fill in the following table:
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