The Atom and Atomic Theory

Radioactivity

100

What types of elements are more likely to undergo radioactive decay?

Larger ones with high numbers of protons and/or neutrons

200

High-energy radiation that emits a photon

Gamma (y)

300

230 Th -> ________________ + 4He + γ        

 90                                             2      

226 Ra

88

400

Which type of radiation would be drawn towards a negatively charged plate?

Alpha

4

2  a

500

Fill in the missing blank

238         0

93 Np + -1 B --> ___________________

            

238

92    U

Vocab

100

Atom with a different number of neutrons

Isotope

200

Atom with a different number of electrons

Ions

300

How can I find atomic mass?

# or protons + # of neutrons

400

Why are atomic masses on the PT decimals instead of whole numbers?

Because they are AVERAGES, meaning we take into account the mass of the isotope and it's abundance to find the avg. atomic mass which is on the PT

500

Define the type of radiation that doesn't bend toward a particlar + or - plate and has no mass.

Gamma (y)

Counting Subatomic Particles

100

How many electrons does Ca^-2

20 + 2 = 22

200

Mass of a Proton, Neutron, Electron?

1, 1, 0

300

Which element has 79 electrons?

Au - Gold

400

Find the atomic mass and atomic number of an atom with 16 protons, 19 neutrons, and 17 electrons

mass - 16+19=35

atomic number = 16 (protons)

500

Find the protons/neutrons/electrons of

¹¹⁹Sn^-2

P: 50

E: 52

N: 69

Avg. Atomic Mass

100

Solve the following to find the average atomic mass of chlorine

35.4 (.7) + 36.2 (.3)

35.4 (.7) + 36.2 (.3)

24.78   +   10.86

= 35.64 amu

200

Why do we use amu (atomic mass units) rather than grams to describe the mass of subatomic particles?

Because atoms are so small!

300

If the mass for zinc is 65.38 amu on the periodic table, what is the most abundant isotope of zinc?

Zn-65

400

Calculate average atomic mass.

Al-25           Al-26             Al-27 

(0.5%)         (4.5%)           (95%)

(25)(.005) + (26)(0.045) + (27)(.95)

0.125        + 1.17          + 25.65

= 26.945 amu

500

Atomic Mass and % Abundance

1. 126 X                     ?

2. 127 X                      84%

Find the missing abundance and calculate the average atomic mass. Then find which element.

100%-84% = 16% missing abundance

126(.16) + 127(.84) = ______

20.16    +   106.68 = 126.84

= Iodine (I)

Miscellaneous

100

What did Dalton theorize?

Had 4 postulates and experimental evidence to support the theory of atoms

200

Why didn't anyone believe Democritus?

No experimental evidence

300

What did the Plum Pudding Model show? Is that model still used?

No, Thomson's Plum Pudding model showed protons and electrons randomly spread out in the atom.

The Nuclear Model shows P+/N in the atom and electrons around the outside of the atom.

400

Explain why Rutherford's Gold Foil experiment was so important and how it influenced our nuclear model of the atom.

He discovered through shooting alpha particles at an atom that it was indeed mostly empty space. Occasionally, the alpha particles deflected as they hit something. This showed that there is a positively charged, dense, and small NUCLEUS

500

2 isotopes of Cobalt exist.

Co-58 and Co-59

Which has more protons? Neutrons? electrons?

Same protons and electrons, but Co-59 has more neutrons.