Chemistry 2.1

An atom of copper is represented by 65 29Cu. How many neutrons are in the nucleus of this atom?

36 65-29=36

Give the nuclear symbol for the isotope of potassium for which A=40?

40 19 K - A = Mass# = 40 - Z = # of Protons = 19 - # of Neutrons = A - Z

There are ________ electrons,_______ protons, and ______ neutrons in an atom of 130 Xe.54.

54, 54, 76

Consider the following selected postulates of Dalton's atomic theory: (i) Each element is composed of extremely small particles called atoms. (ii) Atoms are indivisible. (iii) Atoms of a given element are identical. (iv) Atoms of different elements are different and have different properties. Which of the postulates is(are) no longer considered valid?

(ii) and (iii)

The mass number of an atom of 118Xe is ________.

118

The law of conservation of mass states that mass is neither created nor destroyed during a chemical reaction. This can be gleaned from the third postulate in Dalton's series. Magnesium oxide decomposes into magnesium and oxygen. If 12.09 g of magnesium oxide decomposes to form 7.29 g of magnesium, what mass of oxygen gas is also released in the reaction?

12.09 - 7.29=4.80 g

An atom has a mass number of 32 and 17 neutrons. What is the atomic number of this atom?

15 32 = 17 - x

The atomic number of fluorine is 9. What is the mass number of a fluorine atom with 8 neutrons?

17 Atomic Mass = # of Neutrons + # of Protons # of Protons = Atomic #

200 pm is the same as ________ Å.

2.0

A certain mass of carbon reacts with 13.6 g of oxygen to form carbon monoxide. ________ grams of oxygen would react with that same mass of carbon to form carbon dioxide, according to the law of multiple proportions.

27.2

An atom of 60Ni contains ________ protons.

28

Combination of protons, neutrons, and electrons for the isotope of copper, 63 29Cu?

29 p+, 34 n°, 29 e-

The average atomic weight of copper, which has two naturally occurring isotopes, is 63.5. One of the isotopes has an atomic weight of 62.9 amu and constitutes 69.1% of the copper isotopes. The other isotope has an abundance of 30.9%. The atomic weight (amu) of the second isotope is ________ amu.

64.8 Equation: 2nd Isotope's atomic mass = Avg atomic mass - (atomic mass of 1st isotope) (abundance of isotope 1) / (Abundance of isotope 2) - 100% - 69.1% = 30.9% or .309 Solved Equation: 63.5 - (62.9)(.691) / (.309) = 64.8amu

Which of the following reactions is possible according to Dalton's atomic theory?

N2+O2→2NO

________ are found uncombined, as monatomic species in nature.

Noble gases

In the symbol below, x = ________. x8O

Not enough information to determine

All atoms of a given element have the same ________.

Number of Protons

The subatomic particle with a mass of 1 amu is the ________.

Proton and Neutron

Which subatomic particle(s) are found in the nucleus of the atom?

Protons, Neutrons

Which type of formula provides the most information about a compound?

Structural

The element X has three naturally occurring isotopes. The masses (amu) and % abundances of the isotopes are given in the table below. The average atomic mass of the element is ________ amu. Isotope Abundance Mass 221X 62.870 220.90 220X 23.230 220.00 218X 13.900 218.10

a) 220.30 Average Atomic Mass = Mass x Abundance + x2, x3 - (220.90 x .6287) = 138.87983 + (220.00 x .2323) = 51.106 + (218.10 x .139) = 30.3159 - 138.87983 + 51.106 + 30.3159 = 220.30

Which atom has the largest number of neutrons? a) Silicon-28 b) Calcium-44 c) Argon-38 d) Magnesium-26 e) Sulfur-33

b) Calcium-44 # of Neutrons = Atomic # - Atomic Mass 24 = 44 - 20

Which atom has the smallest number of neutrons? a) neon-20 b) carbon-14 c) oxygen-16 d) fluorine-19 e) nitrogen-14

e) nitrogen-14 7 = 14 - 7