Chap 2: atomic Structure And The Periodic Table

Question 1

describe Dalton’s, the father of modern chemistry, five basic ideas about atoms.

Answer 1

1. All matter is made up of very small, discrete particles called atoms.
2. All atoms of an element are alike in weight, and this weight is different
   from that of any other kind of atom.
3. Atoms cannot be subdivided, created, or destroyed.
4. Atoms of different elements combine in simple whole-number ratios to
   form chemical compounds.
5. In chemical reactions, atoms are combined, separated, or rearranged

Question 2

who discovered the electron

Answer 2

The electron was discovered by J. J. Thomson. by use of cathode rays

Question 3

who discovered there was mostly empty space

between the nucleus and electrons. and later discoverd protons

Answer 3

Rutherford’s experiment using alpha (helium atoms) particles.

Question 4

state the uncertainty,or heisern berg, principle

Answer 4

it states that it is impossible to know the exact location and momentum of an atom at the same time

Question 5

state the Pauli Exclusion Principle.

Answer 5

No two electrons can have the same four quantum numbers.

Question 6

describe Aufbau Principle and Hund’s Rule of Maximum Multiplicity

Answer 6

This principle, that an electron occupies the lowest energy orbital that can receive it, is called the Aufbau Principle. After this, pairing will occur with the addition of one more electron to each orbital. This principle, called Hund’s Rule of Maximum Multiplicity

Question 7

3 new properties of transition metals

Answer 7

■ At least one of their compounds has an incomplete d electron subshell.
■ They are often paramagnetic due to unpaired electrons.

Question 8

3 methods used for the detection of radiation

Answer 8

• Photographic plate
• Scintillation counter.
• Geiger counter.

Question 9

what is radon

Answer 9

• this is a gas formed during spontaneous disintegration of radioactive materials

Question 10

what is transmutation and explain how it can be done artificially

Answer 10

is the conversion of an element to a new element thru radioactivity.
Artificially it can be formed by bombarding the nuclei of a substance with variousparticles from a particle accelerator, such as the cyclotron.

Question 11

Why do transition metals form colored compounds

Answer 11

Bcs electrons in the vacant d orbitals absorb energy and emit it as colored light.