Question

atomic structure test
matching: what is each scientist known for?

1. ______ democritus a) cathode ray tube
2. ______ rutherford b) orbital shapes
3. ______ thomson c) atoms are solid spheres
4. ______ bohr d) gold foil experiment
5. ______ schrodinger e) planetary model

(6 - 37) fill in the missing information for the following elements.

element symbol	atomic number	mass number	number of protons	number of neutrons	number of electrons
		7	3
li+
	8		8	8
		32	16
s-2
	27	59			17
				18
na+	11	23			16
	13
		9
be
	12

counting atoms

1. ______ h2s
2. ______ naoh
3. ______ k2so4

Explanation:

Step1: Recall scientist - discovery pairs

Democritus proposed that atoms are solid spheres.

Step2: Recall Rutherford's work

Rutherford is known for the gold foil experiment.

Step3: Recall Thomson's discovery

Thomson discovered the electron using a cathode - ray tube.

Step4: Recall Bohr's model

Bohr proposed the planetary model of the atom.

Step5: Recall Schrodinger's work

Schrodinger described orbital shapes.

Step6: Recall atomic structure relationships

Atomic number = number of protons. For neutral atoms, number of electrons = number of protons. Mass number = number of protons+number of neutrons. For ions, adjust number of electrons based on charge.
For Ar: Atomic number of Ar is 18, number of protons = 18, number of neutrons = 40 - 18=22, number of electrons = 18.
For Li⁺: Atomic number of Li is 3, mass number is 7, number of neutrons = 7 - 3 = 4, number of electrons = 3 - 1=2.
For an element with 8 protons, it is Oxygen (O), atomic number is 8, mass number = 8 + 8=16, number of electrons = 8.
For S⁻²: Atomic number of S is 16, mass number is 32, number of neutrons = 32 - 16 = 16, number of electrons = 16+2 = 18.
For an element with atomic number 27, it is Co, number of protons = 27, number of neutrons = 59 - 27 = 32, number of electrons = 27.
For Na⁺: Atomic number of Na is 11, number of protons = 11, number of neutrons = 23 - 11 = 12, number of electrons = 11 - 1 = 10.
For an element with atomic number 13, it is Al, number of protons = 13, mass number = 13+16 = 29, number of electrons = 13.
For Be: Atomic number of Be is 4, number of protons = 4, mass number = 9, number of neutrons = 9 - 4 = 5, number of electrons = 4.
For an element with 12 neutrons and assuming it is a neutral atom with 6 protons (Carbon), atomic number = 6, mass number = 6+12 = 18, number of electrons = 6.

Step7: Count atoms in compounds

In H₂S, there are 2 H atoms and 1 S atom, so 3 atoms in total.
In NaOH, there is 1 Na, 1 O and 1 H atom, so 3 atoms in total.
In K₂SO₄, there are 2 K, 1 S and 4 O atoms, so 7 atoms in total.

Answer:

1. C
2. D
3. A
4. E
5. B

Element Symbol	Atomic Number	Mass Number	Number of Protons	Number of Neutrons	Number of Electrons
Li⁺	3	7	3	4	2
O	8	16	8	8	8
S⁻²	16	32	16	16	18
Co	27	59	27	32	27
Na⁺	11	23	11	12	10
Al	13	29	13	16	13
Be	4	9	4	5	4
C	6	18	6	12	6

1. 3
2. 3
3. 7