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Link to Phet build an atom

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Presentation on theme: "Link to Phet build an atom"— Presentation transcript:

1 Link to Phet build an atom

2 Atoms are made of Protons Neutrons Electrons ↓ ↓ ↓
↓ ↓ ↓ Nucleus Nucleus Outside nucleus 1 amu ≈ 1 amu (amu = atomic mass unit =1.66 x g) ↓ ↓ ↓ ATOMIC # ISOTOPE IONS

3 ATOMIC NUMBER – number of protons in the nucleus; determines chemical identity of atom
ISOTOPE- atoms of the same element with a different atomic mass; same # of protons but differ in # of neutrons ION – an atom with a charge (either + or -) + ions have lost electrons; - ions have gained electrons

4 Note: All Lithium atoms have the same atomic #, 3 meaning they all have 3 protons
Note that the different Lithium atoms have different masses due to different #’s of neutrons in the nucleus. Picture shows 3 isotopes of Lithium.

5 Isotopes have different masses due to different number of neutrons

6 Isotopes- atoms of same element with different atomic masses

7 Notation System for Protons, Neutrons, and Electrons
Top right hand corner indicates charge (if nothing is written, charge = 0

8 Atoms may be: Neutral = no charge Positive (+) Negative (-)
Charged atoms = ION Ions form when atoms gain or lose electrons. Gain 1 e- = -1 charge; Gain 2 e- = -2 charge Lose 1 e- = +1 charge; Loses 2e- = +2 charge

9 IONS = CHARGED ATOMS + IONS form when IONs form when e- are LOST
e- are GAINED

10 IONS NEUTRAL ATOM : # PROTONS = # ELECTRONS
+ ION : # PROTONS > # ELECTRONS - ION: # ELECTRONS > # PROTONS

11 Example: Determine # of proton, neutrons and electrons
25 +2 Mg 12 Protons: Atomic # (Lower left) = Neutrons: Mass (top left) – atomic # = Electrons: # protons (bottom left) – charge (top right) =

12 Example: Determine # of proton, neutrons and electrons
25 +2 Mg 12 Protons: Atomic # (Lower left) = 12 Neutrons: Mass (top left) – atomic # = Electrons: # protons (bottom left) – charge (top right) =

13 Example: Determine # of proton, neutrons and electrons
25 +2 Mg 12 Protons: Atomic # (Lower left) = 12 Neutrons: Mass (top left) – atomic # = 13 Electrons: # protons (bottom left) – charge (top right) =

14 Example: Determine # of proton, neutrons and electrons
25 +2 Mg 12 Protons: Atomic # (Lower left) = 12 Neutrons: Mass (top left) – atomic # = 13 Electrons: # protons (bottom left) – charge (top right) = 12 – (+2) = 10 electrons

15 Determine the # of protons, neutrons and electrons.
B Al N P: P: P: N: N: N: E: E: E:

16 Write notation in vertical format and then determine # of proton, neutrons and electrons
C C-13 C-14

17 Note: Isotopes have same # of protons and electrons, different numbers of neutrons

18 Isotopes of Elements in Nature
A sample of the atoms of a naturally occurring element will contain a mixture of the different isotopes of that element.

19 Link to Isotopes

20 Thought Question The mass of boron on the periodic table is listed as 10.8 amu, although there are no atoms of carbon that actually weigh 10.8 amu. Where does the number 10.8 come from? Hint #1: How would you calculate the average of 10 and 11? Hint #2: How would you calculate the average of 10,10,11,11,11,11,11,11,11,11,?

21 Link to Isotopes

22 Average Atomic Mass on the Periodic Table
The atomic mass of an element given on the periodic table represents the weighted average of all of the isotopes of the element, taking into account the relative abundance of each isotope.

23

24 Link to Phet build an atom

25 Homework 1-10 p. 107 , 29-32 29) Explain what we mean when we say an atom has several isotopes. 30)Define atomic # and mass # of the nucleus 31) For a neutral atom the number of protons and electrons is ______ (different or same). 32) The ________ number represents the sum of protons and neutrons in the nucleus.

26 HW 1-10 p. 107 How many protons and neutrons are contained in the nucleus of each of the following atoms? 40a) 39 K c) 84Se e)91Kr

27 HW 1-10 p. 104, #2: A) 0% B) 0.011% C) about 12%
The average mass of a carbon atom is Assuming you could pick up one carbon atom, what is the chance that you would randomly get one with a mass of ? A) 0% B) 0.011% C) about 12% D) % E) greater than 50% F) none of the above. Explain your answer.

28 Homework 1-10 p. 105, #17 17) Chlorine has 2 prominent isotopes Cl-37 and Cl-35. Which is more abundant? How do you know? (Hint: Use the periodic table)


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