Lesson 1 - Atomic Structure & Isotopes

Question 1

John Dalton’s Billiard Ball Model

Answer 1

-Matter is made up of tiny particles
-all atoms of element have identical properties
-atoms of diff elemts have diff properties
-atoms of 2 or more elements can combine in constant ratios to form new substances
-in chemical reactions atoms are not destroyed they simply join together

Question 2

Review: Rutherford’s Gold Foil Experiment what they ASSUMED

Answer 2

-Positively charged beams go through gold foil and they should go right through

Question 3

J.J. Thomson’s Plum Pudding Model

Answer 3

Atoms contain negatively charged electrons

Electrons are evenly distributed through the atom

Atoms are neutral, so there must be positive charges to balance out the negative charges

Question 4

Review: Rutherford’s Gold Foil Experiment what they OBSERVATION

Answer 4

• Showed larger deflections and different directions

Question 5

Review: Rutherford’s Gold Foil Experiment what they CONCLUSION

Answer 5

All of the atom’s positive charge and most of the atom’s mass were concentrated at a tiny point in the centre (the nucleus)

The electrons surrounded the nucleus and occupied most of the atom’s volume, but they only made up a small fraction of the atom’s total mass.

Question 6

Chadwick’s Neutrons

Answer 6

discovered that the nucleus contains neutral particles (neutrons) as well as positively charged particles (protons)

Question 7

Each neutron in an atom has about the same mass as…

Answer 7

each proton in the same atom, but the neutron carries no electrical charge

Question 8

What makes up most of thre mass of the atom

Answer 8

Protons and neutrons

Question 9

What did Bohr suggest about electrons

Answer 9

that electrons surround the nucleus in specific energy levels, each of which can hold a specific number of electrons

Question 10

What makes the atoms of one element different from the atoms of another element?

Answer 10

The number of protons in the nucleus!

Question 11

mass number =

Answer 11

= number of protons + number of neutrons

Question 11

Isotopes

Answer 11

When you have 2 diff versions of an element it is called an isotope.

Question 11

electrons

Answer 11

In a neutral atom, the number of electrons is equal to the number of protons

Question 11

neutrons

Answer 11

The number of neutrons in an atom of an element depends on the mass number of the nucleus

Question 12

Atomic mass

Answer 12

The difference of proportion of diff versions of elements, aka isotopes

Question 12

What can atomic mass help us figure out?

Answer 12

Idenitfy most common isotpes

Question 13

When an atomic mass is not a whole # what does it mean?

Answer 13

it as a weighted average of the masses of all the isotopes

Question 14

Average Atomic Mass (AAM)
equation

Answer 14

• (AAM of isotope A x % of A) + (Atomic Mass of Isotope B x Mass of % B) +……

Calculate problem respectively
% must be a decimal

Question 15

mass spectrometer

Answer 15

identify isotopes and their respective abundances

Question 16

How does mass spectrometer work?

Answer 16

The sample is vaporized (converted to the gas phase by heating)

An electron beam bombards the vapors, which converts the vapors to ions

Because mass spectroscopy measures the mass of charged particles, only ions will be detected, and neutral molecules will not be seen.

Question 17

radioactive decay

Answer 17

The disintegration of unstable isotopes

-The emitted nuclear radiation can take the form of energy or very small particles

Question 18

The most common types of nuclear radiation are:

Answer 18

-alpha
-beta
-gamma

Question 19

Alpha

Answer 19

positively charged particles with the same structure as the nucleus of a helium atom

-stopped by paper

Question 20

Beta (β) particles:

Answer 20

negatively charged particles identical to electrons

-stopped by aluminum

Question 21

Gamma (γ) rays:

Answer 21

a form of high energy electromagnetic radiation

-stopped by lead

Question 22

Radioisotopes

Answer 22

Isotopes that decay to produce nuclear radiation

-For example, ALL of the isotopes of uranium are radioactive

Question 23

Useful Radioisotopes

Answer 23

-iodine
-americium
-cobalt
-carbon

Question 24

As you go up the perodic table the # of shells

Answer 24

decrease

Question 25

As you go down the perodic table the # of shells

Answer 25

increase

Question 26

All elements in a row (period) have the same….

Answer 26

number of energy levels

Question 27

All elements in a column (group) have the same number of….

Answer 27

valence electrons