1. Here we’ll look at how nonmetal atoms form ions.

2. n n n The nucleus we’ve shown here is the nucleus of a fluorine atom. The box for fluorine on the periodic table is shown on the left side of the video here. n p n n p p p n p n p p n p n p The nucleus of a fluorine atom 12 protons 12 neutrons

3. n n n Fluorine has an atomic number of 9 n p n n p p p n p n p p n p n p The nucleus of a fluorine atom 9 protons 10 neutrons atomic number

4. n n n Which means, the nucleus of a fluorine atom has 9 protons. n p n n p p p n p n p p n p n p The nucleus of a fluorine atom 9 protons 10 neutrons

5. n n n Almost all fluorine atoms has 10 neutrons in their nucleus. The number of neutrons does not change when an atom becomes and ion, and neutrons have no effect on charge. n p n n p p p n p n p p n p n p The nucleus of a fluorine atom 9 protons 10 neutrons

6. n n n Because protons all have a positive 1 charge, n p n n p p p n p n p p n p n p Protons all have a +1 charge

7. n n n We’ll replace all the p’s with positive charges n + n n + + + n + n + + n + n +

8. n n n So the nucleus of a fluorine atom has 9 positively charged protons n + n n + + + n + n + + n + n + The nucleus of a fluorine atom has a total charge of +9

9. n n n Therefore, it has a total charge of positive 9 n + n n + + + n + n + + n + n + The nucleus of a fluorine atom has a total charge of +9 +9

10. n n n Electrons have a negative charge. So a neutral atom of fluorine (click) must have 9 electrons to balance the positive 9 charge on the nucleus n + n n + + + n + n + + n + n + The nucleus of a fluorine atom has a total charge of +9 +9 A neutral atom of fluorine has 9 electrons

11. Here, we’ll use the Bohr Model of the atom, (click) where the electrons occupy shells around the nucleus. electrons in shells 2, 8, 2 A neutral atom of fluorine has 9 electrons

12. The first shell has two electrons, the maximum number it can hold. – – electrons in shells 2, 7 A neutral atom of fluorine has 9 electrons

13. A fluorine atom has a total of 9 electrons, so the second shell has a total of 7 electrons. – – electrons in shells 2, 7 A neutral atom of fluorine has 9 electrons ––––– – –

14. – – ––––– – – 9 p 10 n The nucleus has 9 protons and 10 neutrons. Instead of a picture, this is usually simplified by showing a circle (click) with 9 p and 10 n

15. 9 p 10 n – – ––––– – – So this is how we represent a neutral fluorine atom a fluorine atom

16. 9 p 10 n – – ––––– – – We see that in a fluorine atom, the second shell (click) only has 7 electrons, and it can hold 8, so (click) the second shell is not filled a fluorine atom The second shell is not filled, so this atom is unstable

17. 9 p 10 n – – ––––– – – Therefore, this atom is unstable a fluorine atom The second shell is not filled, so this atom is unstable

18. 9 p 10 n – – –––– – – – In order to fill up the second shell and become stable, a fluorine atom (click) must gain one electron a fluorine atom In order to become stable, this atom must gain 1 electron

19. 9 p 10 n – – –––– – – – Right here a fluorine atom In order to become stable, this atom must gain 1 electron –

20. 9 p 10 n – – –––– – – – This now has 9 protons and 10 electrons, so it can no longer be called a fluorine atom. It is (click) now called a fluoride ion. a fluorine atom – a fluoride ion

21. 9 p 10 n – – –––– – – – Notice, the name of this ion ends in “ide” – a fluoride ion

22. 9 p 10 n – – –––– – – – Names of negative ions of non-metals are always changed so they end in “ide” (click) – a fluoride ion Names of negative ions of nonmetals end in “ide”

23. 9 p 10 n – – –––– – – – This ion is stable, – a fluoride ion This ion is stable. It has the same electron arrangement as the noble gas neon: completely filled first and second shells

24. 9 p 10 n – – –––– – – – (start new sentence) Because it has 10 electrons, it has the same electron arrangement as the noble gas neon – a fluoride ion This ion is stable. It has the same electron arrangement as the noble gas neon: completely filled first and second shells

25. 9 p 10 n – – –––– – – – With completely filled first – a fluoride ion This ion is stable. It has the same electron arrangement as the noble gas neon: completely filled first and second shells

26. 9 p 10 n – – –––– – – – And second shells – a fluoride ion This ion is stable. It has the same electron arrangement as the noble gas neon: completely filled first and second shells

27. 9 p 10 n – – –––– – – – A fluoride ion has a total of 9 protons – 9 protons (+) a fluoride ion

28. 9 p 10 n – – –––– – – – And 2 plus eight or 10 electrons – a fluoride ion 9 protons (+) 10 electrons (–)

29. 9 p 10 n – – –––– – – – 9 protons means it has 9 positive charges – a fluoride ion 9 protons (+) 10 electrons (–) +++++++++

30. 9 p 10 n – – –––– – – – And 10 electrons means it has 10 negative charges – a fluoride ion 9 protons (+) 10 electrons (–) +++++++++ ––––––––––

31. 9 p 10 n – – –––– – – – Positive and negative charges neutralize each other, amd what is left over is called the.. – a fluoride ion 9 protons (+) 10 electrons (–) +++++++++ ––––––––––

32. 9 p 10 n – – –––– – – – Net charge – a fluoride ion 9 protons (+) 10 electrons (–) +++++++++ –––––––––– Net charge: – Net charge: –1 Net charge: –

33. 9 p 10 n – – –––– – – – Which is one negative charge – a fluoride ion 9 protons (+) 10 electrons (–) +++++++++ –––––––––– Net charge: – Net charge: –1 Net charge: –

34. 9 p 10 n – – –––– – – – So we can say that the net charge on this ion is negative 1 – a fluoride ion 9 protons (+) 10 electrons (–) +++++++++ –––––––––– Net charge: – Net charge: –1 Net charge: –

35. 9 p 10 n – – –––– – – – Or 1 negative – a fluoride ion 9 protons (+) 10 electrons (–) +++++++++ –––––––––– Net charge: – Net charge: 1– Net charge: –

36. 9 p 10 n – – –––– – – – Which is usually expressed simply as negative. – a fluoride ion 9 protons (+) 10 electrons (–) +++++++++ –––––––––– Net charge: – Net charge: 1– Net charge: –

37. 9 p 10 n – – –––– – – – In the box on the periodic table, the top right hand corner shows the charge on the most common ion of fluorine. We see it is (click) minus 1 – a fluoride ion +++++++++ –––––––––– Net charge: – Net charge: 1– Net charge: – The ion charge

38. 9 p 10 n – – –––– – – – Which is the same as the minus 1 charge shown here for our fluoride ion. – a fluoride ion +++++++++ –––––––––– Net charge: – Net charge: 1– Net charge: – The ion charge

39. Looking on the periodic table, we see that Group 17 nonmetals, or halogens all gain 1 electron (click) to form an ion with a negative 1 charge. Group 17 (Halogens) all gain one electron to form an ion with a – charge

40. The top 4 Group 16 nonmetals all gain 2 electrons (click) to form an ion with a negative 2 charge. The top four Group 16 nonmetals all gain two electrons to form an ion with a 2– charge

41. And the top three Group 15 nonmetals all gain 3 electrons (click) to form an ion with a negative 3 charge. In general, nonmetal atoms gain electrons in order to form stable negative ions. The top three Group 15 nonmetals all gain three electrons to form an ion with a 3– charge