Ch 2 - Elements, Atoms and the Periodic Table

Which of the following substances are elements? a. sodium b. milk c. gold d. water e. air f. liquefied nitrogen

A, C, F

Write the chemical symbol for each element. silver sulfur nitrogen neon bromine oxygen lithium boron

Ag; S; N; Ne; Br; O; Li; B

Give some examples of how the abundance of elements varies.

Elements vary from being a small percentage to more than 30% of the atoms around us.

What element is represented by each chemical symbol? F Fe W Cr Al Sr Rb Bi As Cl Be Pt

Fluorine; Iron; Tungsten; Chromium; Aluminium; Strontium; Rubidium; Bismuth; Arsenic; Chlorine; Berylium; Platnium

What is the mass number of a gallium atom that has 38 neutrons in it?

Ga has an atomic mass # of 31. Therefore the # of protons is 31. Mass #=protons + neutrons= 31+38= 69

Write the chemical symbol for each element bromine boron carbon calcium gold manganese magnesium neon nitrogen silver

Br; B; C; Ca; Au; Mn; Mg; Ne; N; Ag

Explain why it is improper to write CO as the chemical symbol for cobalt.

By convention the second lette in an element is lowercase. This is displaying a compound not a singl element.

Which of the following substances are elements? a. paper b. electricity c. neon d. carbon e. wood f. concrete

C, D

Why are chemical symbols so useful? What is the source of the letter(s) for a chemical symbol?

Chemical symbols are useful to concisley represent the elements present in a substance. The letters usually come from the name of the element.

Describe why Rutherford used the term planetary model to describe his model of atomic structure.

Electrons are in orbit around the nucleus

Which subatomic particle is electrically neutral? Does it exist inside or outside the nucleus?

neutron; in the nucleus

What is the number of protons in the nucleus of each element? 1. aluminum 2. iron 3. carbon 4. sodium 5. oxygen 6. chlorine

1. Al has an atomic # of 13, Therefore, every Al atom has 13 protons 2. Fe has an atomic # of 26, Therefore, every Al atom has 26 protons 3. C has an atomic # of 6, Therefore, every Al atom has 6 protons 4. Na has an atomic # of 11, Therefore, every Al atom has 11 protons 5. O has an atomic # of 8, Therefore, every Al atom has 8 protons 6. Cl has an atomic # of 17, Therefore, every Al atom has 17 protons

How many electrons are present in the atoms of each element? 1. sulfur 2. tungsten 3. argon 4. magnesium 5. potassium 6. iodine

1. S has an atomic # of 16, Therefore in a neutral S atom, there are 16 electrons. 2. W has an atomic # of 74, Therefore in a neutral W atom, there are 74 electrons. 3. Ar has an atomic # of 18, Therefore in a neutral Ar atom, there are 18 electrons. 4. Mg has an atomic # of 12, Therefore in a neutral Mg atom, there are 12 electrons. 5. K has an atomic # of 19, Therefore in a neutral K atom, there are 19 electrons. 6. I has an atomic # of 53, Therefore in a neutral I atom, there are 53 electrons.

How many protons and neutrons are in each atom? 1. 35 17 Cl 2. 127 53 I 3. 197 79 Au 4. 23 11 Na

1. There are 17 protons, & 35-17= 18 neutrons in each nucleus 2. There are 53 protons, & 127-53= 74 neutrons in each nucleus 3. There are 79 protons, & 197-79= 118 neutrons in each nucleus 4. There are 11 protons, & 23-11= 12 neutrons in each nucleus

What is the mass number of a uranium atom that has 143 neutrons in it?

92+143= 235 mass #

What is an element?

An element is the basic chemical building block of matter; it is the simplest chemical substance.

What are atoms?

Atoms are the smallest parts of an element that maintain the identity of that element

hy is it proper to represent the elemental form of helium as He but improper to represent the elemental form of hydrogen as H?

Because Hydrogen exsists as a diatomic molecue (H2) in its elemental form; Helium does not

What is the relationship between the number of protons and the number of electrons in an atom?

In an electrically neutral atom, the number of protons equal the number of electrons

How do isotopes of an element differ from each other?

Isotopes have different numbers of neutrons in their nuclei

How many protons and neutrons does each element have and what is the element name? 200 80 Hg 55 26 Fe 3 1 H 3 2 He 248 95 Am 40 19 K

Mercury (Hg) has 80 protons and 120 neutrons. Iron (Fe) has 26 protons and 29 neutrons. Hydrogen (H) has 1 proton and 2 neutrons. Helium (He) has 2 protons and 1 neutron. Americium (Am) has 95 protons and 153 neutrons. Potassium (K) has 19 protons and 21 neutrons.

What are the charges and the relative masses of the three subatomic particles?

Proton: +1, large Nuetron: 0, large Electron: -1, small

Describe the structure of an atom in terms of its protons, neutrons, and electrons.

Protons and nuetrons are located in a central nucleus, while electrons create a fuzzy cloud around the nucleus.

How many electrons are in neutral atoms of Radon, Tungsten, Chromium, Beryllium, Sulfur, Uranium, Calcium, and Lithium?

Rn = atomic # is 86, so neutrally 86 electrons W = atomic # is 74, so neutrally 74 electrons Cr = atomic # is 24, so neutrally 24 electrons Be = atomic # is 4, so neutrally 4 electrons S = atomic # is 16, so neutrally 16 electrons U = atomic # is 92, so neutrally 92 electrons Ca = atomic # is 20, so neutrally 20 electrons Li = atomic # is 3, so neutrally 3 electrons

What are the atomic numbers of Sulfur, Uranium, Calcium, Lithium, Tungsten, Radon, Chromium, and Beryllium.

S = 16 U = 92 Ca = 20 Li = 3 W = 74 Rn = 86 Cr = 24 Be = 4

What element is represented by each chemical symbol? Na Hg P K I Pb Sn U O F

Sodium; Mercury; Phosphorus; Potassium; Iodine; Lead; Tin; Uranium; Oxygen; Flourine

Why is the atomic number so important to the identity of an atom?

The atomic number defines the identity of an element

What is the mass number of an element?

The mass number is the sum of the number of protons and neutrons in the nucleus of an atom

What is the modern atomic theory?

The modern atomic theory states that all matter is composed of atoms

Complete each sentence. a. 48Ti has _____ neutrons. b. 40Ar has _____ neutrons. c. 3H has _____ neutrons. d. 18O has _____ neutrons. e. 60Ni has _____ neutrons. f. 27I has _____ neutrons.

a. 26 b. 22 c. 2 d. 10 e. 32 f. 74 neutrons = mass # - protons Ex: 48 -22 = 26 neutrons

How many protons are in the nucleus of each element? a. radon b. tungsten c. chromium d. beryllium e. sulfur f. uranium g. calcium h. lithium

a. Atomic # = 86, so 86 protons b. Atomic # = 74, so 74 protons c. Atomic # = 24, so 24 protons d. Atomic # = 4, so 4 protons e. Atomic # = 16, so 16 protons f. Atomic # = 92, so 92 protons g. Atomic # = 20, so 20 protons h. Atomic # = 3, so 3 protons

State the number of protons, neutrons, and electrons in neutral atoms of each isotope. a. 131I b. 40K c. 201Hg d. 19F e. 3H f. 133Cs g. 56Fe h. 207Pb

a. Iodine has an atomic # of 53. Therefore, the # of electrons and protons is 53 and 131-53= 78 neutrons. b. Potassium has an atomic # of 19. Therefore, the # of electrons and protons is 19 and 40-19= 21 neutrons. c. Mercury has an atomic # of 80. Therefore, the # of electrons and protons is 80 and 201-80= 121 neutrons. d. Fluorine has an atomic # of 9. Therefore, the # of electrons and protons is 9 and 19-9= 10 neutrons. e. Hydrogen has an atomic # of 1. Therefore, the # of electrons and protons is 1 and 3-1= 2 neutrons. f. Cesium has an atomic # of 55. Therefore, the # of electrons and protons is 55 and 133-55= 78 neutrons. g. Iron has an atomic # of 26. Therefore, the # of electrons and protons is 26 and 56-26= 30 neutrons. h. Lead has an atomic # of 82. Therefore, the # of electrons and protons is 82 and 207-82= 125 neutrons.

Which of the following elements exist as diatomic molecules? a. helium b. hydrogen c. iodine d. gold e. chlorine f. potassium g. silver h. oxygen

b, H2 c, I2 e, Cl2 h, O2

Which is smaller—an electron or a helium atom?

electron

Why is the planetary model not an appropriate way to describe the structure of an atom?

electrons form a fuzzy cloud around the nucleus, not a certain specific orbits

Protons are among the (most, least) massive subatomic particles, and they are found (inside, outside) the nucleus.

most; inside

Electrons are among the (most, least) massive subatomic particles, and they are found (inside, outside) the nucleus.

least; outside

Electrons account for the (majority, minority) of the (mass, volume) of an atom.

majority; mass

Which subatomic particle has a positive charge? Which subatomic particle has a negative charge?

proton; electron