atoms and subatomic particles for grade 8

learn about the three subatomic particles and the equation

1. A t o m s a n d S u b a t o m i c P a r t i c l e s 3 rd Quarter Grade 8 Science

2. A t o m s The smallest possible unit into which matter can be divided, while still maintaining its properties

3. A t o m s “Indivisible” It was once thought that atoms were the smallest things in the universe and could not be divided

4. P r o p e r t i e s o f S u b a t o m i c P a r t i c l e s PARTICLES SYMBOL LOCATION CHARGE Proton Inside the nucleus +1 Neutron Inside the nucleus Electron Outside the nucleus -1 PARTICLES SYMBOL LOCATION CHARGE Proton Inside the nucleus +1 Neutron Inside the nucleus Electron Outside the nucleus -1

5. P r o t o n Ernest Rutherford Equal to the atomic number and electron of an atom Contribute to the atomic mass

6. N e u t r o n The neutron of an element is the difference between mass number and atomic number: = A - Z   Element A Z Carbon (C) 12 6 6 Phosphorus (P) 30 15 15 Gold (Au) 197 79 118 Element A Z Carbon (C) 12 6 6 Phosphorus (P) 30 15 15 Gold (Au) 197 79 118

7. E l e c t r o n Sir John Joseph Thomson Tiny compared to protons and neutrons

8. E l e c t r o n The number of an electron in a neutral atom is equal to the number of proton . Element Carbon (C) 6 6 Phosphorus (P) 15 15 Gold (Au) 79 79 Element Carbon (C) 6 6 Phosphorus (P) 15 15 Gold (Au) 79 79

9. I o n s Charged particle that typically results from a loss or gain of electrons Two types: Anion = negatively charged particle Cation = positively charged particle

10. An ion is an atom, or group of atoms, that has a net positive or negative charge. cation – ion with a positive charge If a neutral atom loses one or more electrons it becomes a cation. anion – ion with a negative charge If a neutral atom gains one or more electrons it becomes an anion. Na 11 protons 11 electrons Na + 11 protons 10 electrons Cl 17 protons 17 electrons Cl - 17 protons 18 electrons

11. E l e c t r o n The no. of an electron in ions is the difference between the no. of proton and the charge: - charge   Element charge 17 -1 18 3 +1 2 12 +2 10 Element charge 17 -1 18 3 +1 2 12 +2 10 i

12. P r a c t i c e E x e r c i s e 5 Compute for the electron of the following ions. Element charge Element charge

13. C o m p o s i t i o n o f a n a t o m

14. C h e m i c a l S y m b o l o f a n E l e m e n t   Mass Number Atomic Number Symbol of the Element

15. A t o m i c N u m b e r Atomic number (Z) of an element is the number of protons in the nucleus of each atom of that element. Element Atomic No. No. of Protons Carbon (C) 6 6 Phosphorus (P) 15 15 Gold (Au) 79 79

16. M a s s N u m b e r Mass number (A) is the number of protons and neutrons in the nucleus of an isotope: A = +   Element A Carbon (C) 6 6 12 Phosphorus (P) 15 15 30 Gold (Au) 79 118 197 Element A Carbon (C) 6 6 12 Phosphorus (P) 15 15 30 Gold (Au) 79 118 197

17. P r a c t i c e E x e r c i s e 6   FIND EACH OF THESE: number of protons number of neutrons number of electrons atomic number mass number

18. P r a c t i c e E x e r c i s e 6   FIND EACH OF THESE: number of protons number of neutrons number of electrons atomic number mass number element

19. P r a c t i c e E x e r c i s e 7

20. Element Atom 1 Atom 2 Number of Protons Number of Neutrons Mass Number Element P r a c t i c e E x e r c i s e 7

21. Q u i z 3 Subatomic Particles

22. Ions Protons Charge Electrons Cat ion or An ion 1. 2. 3. 4. 5. 6. Ions Protons Charge Electrons Cat ion or An ion

23. I d e n t i f i c a t i o n   FIND EACH OF THESE: number of protons number of neutrons number of electrons atomic number mass number element name

24. I S O T O P E S Atoms of the same element with the same atomic number but different mass number These atoms differ in the number of neutrons

25. I S O T O P I C N O T A T I O N A shorthand notation for a nucleus that shows the mass number, atomic number and the symbol. Example: U-238 would be  

26. N A M I N G I S O T O P E S In naming isotopes, the mass number can be placed after the name of the element: Carbon-12 Carbon-13 Carbon-14

27. Isotopic Notation Atomic Number Mass Number Number of Protons 19 9 16 Number of Neutrons P r a c t i c e E x e r c i s e 8