Atomic Structure

Question 1

Protons

Answer 1

• Positively charged +1
• Mass of one atomic mass unit (amu)
• Atomic number = proton count
  
  • In a neutral atom, atomic number also = electron count

Question 2

Neutrons

Answer 2

• Mass is just slightly more than one amu
• neutral charge
• Mass number = sum of protons and neutrons in average atom
  
  • This means that mass number is the average of all the isotopes.

Question 3

Isotopes

Answer 3

Isotopes are atoms that share an atomic number (proton count) but have a different mass number (differing neutron count)

Question 4

^A_ZX

Answer 4

• A = mass number
• Z = atomic number
• X = atom

Question 5

Avogadro’s number:

Answer 5

Avogadro’s number: 6.022 X 10²³

Think 6:02 on October 23 (10/23)

Question 6

Isotope:

Answer 6

An element with a different number of neutrons, written with mass number (carbon-12)

Question 7

Do isotopes generally exhibit the same chemical properties as the element?

Answer 7

Yes, because they have the same number of protons and electrons.

Question 8

Planck’s constant (h):

Answer 8

h = 6.626 X 10^-34 J • s

Question 9

Atoms of any element will generally exist in the ground state unless subjected to…

Answer 9

Extremely high temperatures or irradiation. All systems tend toward minimal energy.

Question 10

Speed of light in a vacuum (c):

Answer 10

c = 3.00 X 10⁸ m/s

Question 11

What is the formula for electromagnetic energy?

Answer 11

E = (h*c)/wavelength

Question 12

When an electron is excited to a higher energy level, what occurs?

Answer 12

Energy is absorbed at specific wavelengths.

Question 13

Change in energy is endothermic (negative) when an atom’s electron state moves in what direction?

Answer 13

• delta E is endothermic due to absorption secondary to an atom moving to a higher (excited) energy level.

Question 14

Change in energy is exothermic (positive) when an atom’s electron state moves in what direction?

Answer 14

+ delta E is secondary to the atom moving to the ground state, which releases photons and is exothermic.

Question 15

Bohr Model

Answer 15

Bohr postulated that electrons follow a clearly defined circular pathway or orbit at a fixed distance from the nucleus.

Question 16

Quantum Mechanical Model of Atoms

Answer 16

Electrons move rapidly in extraordinarily complex patterns within regions of space around the nucleus called orbitals.

Question 17

Heisenberg uncertainty principle

Answer 17

It is impossible to simultaneously determine, with perfect accuracy, the momentum and the position of an electron.

Question 18

What are the four Quantum numbers?

Answer 18

n, l, m_l, m_s