Atomic structure, Symbolism, Chemical formulas; The periodic table; Molecules, compounds & formulas; Ionic compounds – formulas, names & properties

Question 1

[12] Describe the nucleus of an Atom. (3)

Answer 1

▪small, dense, positive core
▪made of protons and neutrons ▪particles held together by the
“strong nuclear force”
o stronger than +/+ repulsion

Question 2

What did the Greeks believe believe about elements?

Answer 2

ancient Greeks believed there were four: Earth, Fire, Water, Air

Question 3

What is important about the study of Alchemy? (3)

Answer 3

• attempts to transmute “base” metals (i.e., cheap ones) into gold
• went on for about 2000 years without success…
• …but lead to discovery of many elements and chemicals (e.g., mineral acids)

Question 4

Who was the first contributor of extraction of metals from minerals?

Answer 4

geologist Georg Bauer a.k.a. Georgius Agricola (German 1494 – 1555)

Question 5

Who pioneered the Medicinal use of minerals?

Answer 5

• Philippus Theophrastus Bombastus von Hohenheim a.k.a. Paracelsus (Swiss, 1493 – 1541) did this and also a lot of synthetic chemistry

Question 6

Who first started to study about gases? (4)

Answer 6

• Robert Boyle (English, 1627 – 1691): among first to “measure” things
• did not believe in Greeks’ four elements
• his idea: an element = a substance that cannot be further broken down
• did not believe metals were elements he dabbled in alchemy…

Question 7

What is the history behind Phlogiston?

Answer 7

• fire-like entity within combustible materials, released by burning
• since metal oxides are heavier than the metal from which they come,
  phlogiston was presumed to have negative mass! * phlogiston theory disproved once:
  *Joseph Priestly (English, 1733 – 1804) discovered oxygen
  *Antoine Lavoisier (French, 1743 – 1794) added rigour and explanation

Question 8

What was the chemical revolution? (4)

Answer 8

• turning alchemy into science (late 1700s)
• Lavoisier = the father of modern chemistry
• introduced systematic terminology and quantitative experimentation
• and a new solid backbone for chemistry: Law of Conservation of Matter

Question 9

What was John Dalton’s atomic theory?

Answer 9

1. All matter is made of atoms.
2. Allatomsofanelementareidentical.notexactlytrue…
3. A given compound always has the same relative #s and types of atoms.
4. Chemical reactions involve the reorganization of atoms, but the atoms
   themselves are not changed.  except in nuclear reactions.

Question 10

One of the following historical statements is incorrect. Which one is it?
A. The Greeks used the term “atom” long before John Dalton did
B. Alchemists made many important discoveries but they were driven by an
impossible goal
C. Antoine Lavoisier was a famous alchemist who worked in the Middle Ages
D. Phlogiston was once widely accepted, as a substance with negative mass that was released when matter burned

Question 11

[12] Describe what surrounds the nucleus of an Atom. (3)

Answer 11

▪electrons in motion
(tiny negative particles)
▪stay within ~10^−8 cm of nucleus ▪NOT in orbits, more like clouds

Question 12

The identity of element determined by _________________________

Answer 12

[14] the number of protons in atom

Question 13

Atoms are electrically ……

Answer 13

NEUTRAL: # protons = # electrons

Question 14

What is describes the positivity of an Atom?

Answer 14

POSITIVE: charge on nucleus = # protons

Question 15

What is describes the negativity of an Atom?

Answer 15

charge on electrons = # electrons
counter each other

Question 16

Atomic symbol reveals…

Answer 16

[14] nuclear composition of atoms

Question 17

[15] Fill in the blanks

Answer 17

Na:
Au:

Question 18

What characteristic determines the element type of any individual atom?

Answer 18

A. the number of electrons around its nucleus
B. the number of neutrons in its nucleus
C. its atomic number
D. its mass number
E. its charge

Question 19

What are Isotopes?

Answer 19

Atoms with same # protons (thus same element) thus same # electrons
BUT different # neutrons (thus different mass)

Question 20

Give an example of Isotopes of Hydrogen.

Answer 20

Hydrogen:
mass of 1 atom of ¹H (protium) = 1 amu (1 p+ + 0 n0)
mass of 1 atom of ²H (deuterium) = 2 amu (1 p+ + 1 n0)
mass of 1 atom of ³H (tritium) = 3 amu (1 p+ + 2 n0)

Question 21

Which set of subatomic particles describes the composition of an isotope of iron (⁵⁸Fe) ?

Answer 21

A. 26 neutrons, 32 protons, and 26 electrons
B. 32 neutrons, 26 protons, and 26 electrons
C. 26 neutrons, 26 protons, and 32 electrons
D. 26 neutrons, 26 protons, and 26 electrons

Question 22

[18] Describe what a spectrometer does.

Answer 22

Typically based on the analysis of the electromagnetic radiation emitted by the atoms in an element.
▪Atoms ionized to form CATIONS (= positively charged ions) ▪ Electric field pulls cations through magnetic field
▪ Ions are deflected — heavy ions deflect LESS
 IONS SEPARATED BY MASS

Question 23

An element (“E”) has several naturally occurring isotopes, with the following abundances:
⁷²E, 54.5% ⁷³E, 15.6% 74E, 29.9%
The most reasonable atomic weight for this element would be:
A. 72.1
B. 72.8
C. 73.4
D. 73.8
E. 74.0

Answer 23

B