What is an ISOTOPE? EXAM PRACTICE Q. Explain what is meant by the term isotope. Learn this: Isotopes are different forms of the same element, which have the SAME number of PROTONS but DIFFERENT numbers of NEUTRONS

TASK 1 Spot the Pair You will be shown 4 atoms Identify the 2 isotopes

protons neutrons

35 Da 14 35 Da 15 32 Da 16 32 Da 15

47 60 46 47 60 47 57 48 57 No. of electrons No. of neutrons No. of protons 47 60 46 No. of electrons No. of neutrons No. of protons 47 60 No. of electrons No. of neutrons No. of protons 47 57 No. of electrons No. of neutrons No. of protons 48 57

Gymnium-95 Gymnium-96 Gymnium-96 Gymnium-98 Electrons:48 Neutrons: 47 Protons:48 Gymnium-98 Neutrons:47

Task 2 Complete the worksheet on ISOTOPES

Look at your periodic table Look at your periodic table. The atomic masses are all whole numbers except for…. 35.5 Cl Chlorine 17 The relative Atomic Mass of Chlorine is recorded as 35.5. How many neutrons does it have? 35.5 – 17 = 18.5 You can’t have half a neutron. So how can this be explained? 63.5 Cu Copper 29

What are the Numbers all About? 75% of the Chlorine in existence is Cl35 25% of the Chlorine in existence is Cl37 35 35 35 35 35 35 35 35 35 35 ISOTOPES 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 37 37 37 37 37 35 35 35 35 35 37 37 37 37 37 37 37 37 37 37 37 37 37 37 37 37

What are the Numbers all About? Total number of protons & neutrons in a specific isotope From calculations involving all isotopes Relative Atomic Mass (Ar) Mass Number 35 Cl 17 37 Cl 17 35.5 Cl 17 Atomic Number (Proton Number)

What are the Numbers all About? Total number of protons & neutrons in a specific isotope Relative Atomic Mass (Ar) From calculations involving all isotopes Mass Number 64 Zn 30 66 Zn 30 65.409 Zn 30 67 Zn 30 68 Zn 30 70 Zn 30

Isotopes of hydrogen Protium Deuterium Tritium 1 proton, 0 neutron, 1 electron 1 proton, 1 neutron, 1 electron 1 proton, 2 neutron, 1 electron

1 H Hydrogen has RAM of 1 because 99% of the hydrogen atoms on earth are Hydrogen-1 Bromine has RAM of 80 as it is found here as 50% Bromine-79 and 50% Bromine-81. 80 Br 35

How to calculate R.A.M (Ar) Copper has two main isotopes. 69% are Copper-63 31% are Copper-65 Can you guess what the R.A.M will be close to? RAM = (mass no 1 x % abundance 1) + (mass no 2 x % abudance 2) 100

The periodic table states that the Relative Atomic Mass (Ar) of Boron is 11 Boron has two naturally occurring isotopes. 80% of all Boron is B11 (6 neutrons) 20% of all Boron is B10 (5 Neutrons) Calculate the average relative atomic mass of Boron.

The periodic table states that the Relative Atomic Mass (Ar) of Magnesium is 24 Magnesium has three naturally occurring isotopes. 79% of all Magnesium is Mg24 (12 neutrons) 11% of all Magnesium is Mg25 (13 Neutrons) 10% of all Magnesium is Mg26 (14 neutrons) Calculate the average relative atomic mass of Mg