CHEM 108 Test: Atomic Structures

Atomic Symbol A Z X What does each letter represent?

"A" is the mass number (total number of proton and neutrons) "Z" is the atomic number (number of protons) "X" is the chemical symbol of the element

How many protons, neutrons, and electrons are present in the following element of neon? 22Ne In a neutral atom, the number of protons must be equal to the number of electrons, as the protons are positively charged and the electrons are negative charged.

10 Protons 12 Neutrons 10 Electrons

How many protons and neutrons are present in the following element of iron? 56Fe

26 Protons and 30 neutrons

Anion

A negatively charged ion

Cation

A positively charged ion

How many neutrons are present in the following element of copper? 64Cu (Look at periodic table) A. 35 B. 29 C. 64 D. 63.45

A. 35

Consider the following designation for an isotope of phosphorus-31: A Z P "A" is the mass number, "Z" is the atomic number, and "X" is the chemical symbol of the element. What numbers should be used for the letter "A" and the letter "Z"? A. A = 31, Z = 15 B. A = 30, Z = 15 C. A = 15, Z = 31 D. A = 31, Z = 17

A. A = 31, Z = 15 A = Mass number, protons plus neutrons. ( 15 protons and 16 neutrons) Z = Atomic number, number of protons

Which atom has the same number of electrons as a Ca2+ ion? A. Ar B. K C. Ti D. Ca

A. Ar

Which atom has the same number of electrons as a P3- ion? A. Ar B. Mg C. Al D. P

A. Ar

If calcium were to lose two electrons, what would be the resulting ion? A. Ca2+ B. Ar C. K D. Ca2-

A. Ca2+

If nitrogen were to gain three electrons, what would be the resulting ion? A. N3- B. N3+ C. He D. Ne

A. N3-

What symbol designates an ion that contains 8 protons and 10 electrons? A. O2- B. O2+ C. Ne D. B2+

A. O2- O2- indicates an ion of oxygen having two extra electrons. I.e., since an oxygen atom normally has 8 protons and 8 electrons, this ion has 10 electrons (-10 charge) and 8 protons (+8 charge) giving it a charge of -2 (-10 + 8 = -2).

An ion has a 3- charge and 18 electrons. What is the identity of the element? (Look at your periodic table). A. P B. Ar C. Sc D. Mg

A. P If an ion has a 3-, then the atom gained three electrons to form the ion. If the ion has 18 electrons after gaining three, then it must have started with 15 electrons. A neutral atom with 15 electrons must have 15 protons, which determines the identity of the element as P.

An ion is a charged atom, due to ________________

An unequal number of protons and neutrons

Select the atomic symbol that would represent an isotope with 56 protons and 82 neutrons. A. 138 82 Pb B. 138 56 Ba C. 56 82 Fe D. 138 57 La

B. 138 56 Ba

Which of the following would be an isotope of 58Ni? A. 58Co B. 60Ni C. 65Zn D. 55Mn The mass number is written as a superscript in front of the elemental symbol.

B. 60Ni

Which element has a total of 79 protons? (Look at periodic table) A. Selenium, Se B. Gold, Au C. Platinum, Pt D. Bromine, Br

B. Gold, Au

An ion is a charged atom, due to an unequal number of protons and electrons. If the number of protons is greater than the number of electrons, a positively charged ion, or cation, is formed. If the number of protons is less than the number of electrons, a negatively charged ion, or anion, is formed. Remember that the number of protons cannot be altered, as the number of protons determines the identity of an element. What would be required for magnesium to form the ion Mg2+? A. Magnesium would gain two protons B. Magnesium would lose two electrons C. Magnesium would lose two protons D. Magnesium would gain two electrons

B. Magnesium would lose two electrons

Which of the following pairs are isotopes of each other? A. 55Mn and 55Fe B. 18O and 18F C. 70Ga and 69Ga D. 39K and 45Sc

C. 70Ga and 69Ga 70Ga and 69Ga are isotopes of one another, as they are the same element and therefore, have the same number of protons. However, 70Ga and 69Ga have a different mass number, resulting in a different number of neutrons.

An ion has a 2+ charge and 18 electrons. What is the identity of the element? A. S B. Ar C. Ca D. K

C. Ca

Which isotope has the same number of neutrons as N-15? A. F-19 B. N-14 C. O-16 D. C-12

C. O-16 O-16 has the same number of neutrons as N-15. N-15 has 7 protons as given by its atomic number and 8 neutrons because 15-7 = 8. O-16 has 8 protons as given by its atomic number and 8 neutrons because 16-8 = 8.

What symbol designates an ion that contains 30 protons and 28 electrons? A. Ni2- B. Zn2- C. Zn2+ D. Ni2+

C. Zn2+ 30 protons (+30) 28 Electrons (-28) 30 + (-28) = +2.

Select the atomic symbol that would represent an isotope with 13 protons and 14 neutrons. A. 14 16 N B. 13 6 C C. 27 14 Si D. 27 13 Al

D. 27 13 Al The isotope Al - 27 has 13 protons and 14 neutrons. (13 + 14 = 27)

What would be required for aluminum to form the ion Al3+? A. Aluminum would gain 3 protons B. Aluminum would lose 3 protons C. Aluminum would gain 3 electrons D. Aluminum would lose 3 electrons

D. Aluminum would lose 3 electrons

Which atom has the same number of electrons as a Ca2+ ion? A. Ca B. Ti C. K D. Ar

D. Ar Ar has the same number of electrons as the Ca2+ ion. Neutral calcium atoms contain 20 protons and 20 electrons. To form the Ca2+ ion, two electrons were lost, leaving Ca2+ with 18 electrons. Argon has 18 protons and is a neutral atom, so it also has 18 electrons.

Which isotope has the same number of neutrons as Ca-42? A. Mo-96 B. Sc-45 C. Ti-48 D. Ar-40

D. Ar-40

An ion has a 3- charge and 18 electrons. What is the identity of the element? A. Mg B. Sc C. Ar D. P

D. P The element is P. If an ion has a 3-, then the atom gained three electrons to form the ion. If the ion has 18 electrons after gaining three, then it must have started with 15 electrons. A neutral atom with 15 electrons must have 15 protons, which determines the identity of the element as P.

Isotopes are atoms of the same element that have ________ number of protons but a _______ number of neutrons.

Isotopes have the same number of protons but a different number of neutrons. Therefore, isotopes have the same atomic number (number of protons) but a different mass number (number of protons plus number of neutrons). Typically, the mass number is written as a superscript in front of the elemental symbol.

If the number of protons is less than the number of electrons, a _____________ charged ion, or anion, is formed.

Negatively -

If the number of protons is greater than the number of electrons, a ___________ charged ion, or cation, is formed.

Positively +

Of protons, neutrons, and electrons, which one(s) are found in the nucleus and which one(s) are found outside the nucleus?

Protons and neutrons are found in the nucleus, and electrons are found outside the nucleus.

Isotopes are atoms of the same element that have the ___________ number of protons but a _________ number of protons

The same number of protons but a different number of protons