Flashcard Set71 cards

Atoms Molecules and Atomic Theory

Generated from Atoms Molecules and Atomic Theory

Free to study. No account needed.

1 / 71

All 71 cards

1
What is an atom?
An atom is the smallest unit of matter that retains the properties of an element.
2
Which three atoms are the most abundant in the human body?
Hydrogen, oxygen, and carbon are the top three atoms found in the human body.
3
What is a molecule?
A molecule is a chemical structure composed of two or more atoms that are chemically bonded together.
4
Why do atoms bond with each other to form molecules?
Atoms form chemical bonds in order to become more stable.
5
What did John Dalton identify as the smallest reacting particle of an element?
Dalton identified the atom as the smallest reacting particle of an element.
6
State the Law of Conservation of Mass formulated by Lavoisier in 1787.
Matter is neither created nor destroyed in a chemical reaction, meaning the total mass of the reactants equals the total mass of the products.
7
What does the Law of Definite Proportions (or Law of Constant Composition) state?
All samples of a pure compound contain the same elements in the exact same proportion by mass.
8
According to John Dalton's atomic theory, what happens to atoms during an ordinary chemical reaction?
Atoms move from one substance to another, but no atom disappears or is converted into an atom of another element.
9
Who proposed the Law of Definite Proportions between 1797 and 1804?
Joseph Proust proposed the Law of Definite Proportions (also known as the law of constant composition).
10
According to the first scientific atomic model, in what numerical proportion do atoms combine to form compounds?
Compounds are formed when atoms combine in simple whole-number ratios.
11
How did cathode rays behave when exposed to electrically charged plates in J.J. Thomson's experiments?
The glowing beam bent away from the negative plate and toward the positive plate, demonstrating that the particles carry a negative charge.
12
What observation in Thomson's cathode ray experiments showed that electrons are universal components of all atoms?
The cathode ray beam exhibited the same deflection behavior regardless of which metal was used to make the electrodes.
13
Why did the mass of cathode ray particles prove they were subatomic pieces rather than intact atoms?
Because the particles were found to be much lighter than atoms, meaning they had to be smaller constituent parts from inside atoms.
14
Which historic 1907 experiment first demonstrated the existence of the atomic nucleus?
Ernest Rutherford's Gold Foil Scattering Experiment, where alpha particles were directed at thin gold foil.
15
What did Rutherford conclude about the volume of an atom from the gold foil scattering results?
He concluded that an atom's volume consists mostly of empty space, with a small, dense, positively charged nucleus at its center.
16
Why was the deflection of alpha particles in Rutherford's experiment compared to shooting a bullet at tissue paper and having it bounce back?
Alpha particles were expected to pass straight through, but some struck the small, dense, positively charged nucleus and were deflected backward.
17
Where in the atom is the proton located, and what charge does it carry?
The proton is a positively charged subatomic particle located in the nucleus.
18
Why do dense materials like lead block radiation much more effectively than soft tissue?
Dense materials have tightly packed atoms with more atoms per unit of volume, which increases the probability of particle collisions and absorption.
19
Which subatomic particle gives an atom its specific chemical identity?
The proton gives the atom its identity.
20
Where are electrons located relative to the nucleus, and how are they described in atomic structure?
Electrons are tiny, negatively charged subatomic particles that surround and zoom around the outside of the nucleus.
21
How is one atomic mass unit (amu) formally defined?
One atomic mass unit (amu) is defined as 1/12 of the mass of a carbon-12 atom.
22
What electrical charge does a neutron have, and where in an atom is it found?
A neutron has no electrical charge (0) and resides within the atomic nucleus.
23
What capitalization rule applies to every element's chemical symbol?
Only the first letter of a chemical symbol is capitalized.
24
What does an atom's Atomic Number (Z) represent, and what does it define?
The atomic number (Z) is the number of protons in an atom's nucleus, and it uniquely defines the identity of the element.
25
What quantities make up an atom's Mass Number (A), and what does this number indicate?
Mass Number (A) is the sum of protons and neutrons, and it identifies the specific isotope of the atom.
26
How does the mass of a proton or neutron compare quantitatively to the mass of an electron?
The mass of a proton or neutron is approximately 1,840 times the mass of an electron (mass p = mass n = 1840 × mass e⁻).
27
For a neutral sodium-23 atom with an atomic number of 11, how many protons, electrons, and neutrons are there?
It has 11 protons, 11 electrons, and 12 neutrons (calculated as 23 − 11 = 12).
28
In standard nuclear symbol notation written as A/Z X, what values do A and Z represent?
Z represents the atomic number (number of protons), while A represents the mass number (total number of protons and neutrons).
29
What is the complete nuclear symbol for an isotope of antimony (Sb, Z = 51) with 73 neutrons?
Its nuclear symbol is 124/51 Sb, calculated by adding atomic number (51) and neutrons (73) to get a mass number of 124.
30
What Latin term meaning "water silver" serves as the linguistic origin for mercury's symbol?
The Latin term is Hydrargyrum, which translates to "water silver".
31
What defines two atoms as isotopes of the same element?
Isotopes have the same number of protons but differ in their number of neutrons.
32
How do isotopes of an element compare in their chemical and physical properties?
They are chemically identical, but they differ physically in mass and stability.
33
What materials can be dated with radiocarbon dating, and up to what approximate age?
It is used to date bones, ancient wood, artifacts, and fossils up to approximately 50,000 years old.
34
How do mass spectrometers detect isotopes and assist in periodic table data collection?
They separate isotopes by mass to provide precise mass values and percent abundances used to calculate atomic mass data.
35
What are the names and neutron counts of the three isotopes of hydrogen?
Protium has 0 neutrons, deuterium has 1 neutron, and tritium has 2 neutrons.
36
Why does the periodic table list a weighted average mass instead of the mass of a single isotope?
Most elements naturally occur as a mixture of two or more isotopes, so the table lists the weighted average mass across that sample.
37
Which two elements exist naturally as liquids at standard elemental state?
Mercury (Hg), which is a metal, and bromine (Br₂), which is a nonmetal.
38
How are elements ordered across the periodic table, and what does each period represent?
Elements are arranged by increasing atomic number (Z), where each period corresponds to an electron shell or energy level.
39
How do metals and nonmetals differ in appearance, conductivity, and flexibility?
Metals are shiny, malleable, and good conductors, whereas nonmetals are dull, brittle, and poor conductors.
40
Which group numbers designate transition metals versus representative elements, and how do their charge patterns differ?
Transition metals are Groups 3–12 and have variable charges and colorful ions; representative elements are Groups 1–2 and 13–18 and display predictable charge patterns.
41
How do you calculate the mass of a single arsenic (As) atom using its atomic mass and Avogadro's number?
Divide the atomic mass of arsenic (74.92 g) by Avogadro's number (6.022 × 10²³ atoms), which gives 1.244 × 10⁻²² g.
42
What strong forces hold atoms together within a molecule?
Covalent bonds are the strong forces that hold the atoms together.
43
What types of elements are most commonly involved when atoms combine to form a molecule?
The atoms involved in forming molecules are often nonmetals.
44
When are subscripts included after a chemical symbol in a molecular formula?
Subscripts are written only when more than one atom of that given type is present in the molecule.
45
What defines chemical isomers?
Isomers are compounds that share the same molecular formula but have different connectivity of their atoms.
46
An ion with a positive charge formed by losing electrons is called a(n) [blank].
A cation.
47
Why does an atom take on a positive charge when it loses electrons?
Losing electrons means giving away negativity, leaving behind more positive protons than negative electrons.
48
How many protons and electrons are present in an Al³⁺ ion?
An Al³⁺ ion has 13 protons and 10 electrons.
49
What are the chemical symbols and charges for calcium, phosphorus, iodine, and sulfur ions?
Calcium is Ca²⁺, phosphorus is P³⁻, iodine is I⁻, and sulfur is S²⁻.
50
Why are molecular formulas considered less useful than structural formulas?
While molecular formulas give the composition of a molecule, they reveal nothing about the way the atoms fit together.
51
In a nuclear symbol, what quantity is represented by the symbol Z?
Z represents the atomic number, which equals the number of protons (p⁺) in the atom.
52
How do metals and nonmetals differ in the types of ions they typically form?
Metals tend to lose electrons to form positively charged cations, whereas nonmetals tend to gain electrons to form negatively charged anions.
53
What constitutes an ionic compound?
An ionic compound consists of both cations and anions, such as table salt containing sodium and chloride ions in equal proportion.
54
Under what condition do ionic compounds conduct electricity?
Ionic compounds conduct electricity when they are dissolved in water.
55
How do ionic compounds differ from molecular compounds in their electron interactions?
In ionic compounds, electrons are transferred between atoms, whereas in molecular compounds, electrons are shared.
56
What types of elements combine to form ionic compounds versus molecular compounds?
Metals and nonmetals tend to form ionic compounds, whereas two nonmetals form molecular compounds.
57
According to the text, which two formulas represent the only common polyatomic cations?
The only two common polyatomic cations listed are NH₄⁺ and Hg²⁺; all other common polyatomic ions are anions.
58
What are the characteristic ionic charges of Group 1 metals, Group 2 metals, and aluminum?
Group 1 metals have a +1 charge, Group 2 metals have a +2 charge, and aluminum (Al) has a +3 charge.
59
What is an oxoanion?
An oxoanion is a polyatomic ion that contains oxygen attached to another element.
60
What is a polyatomic ion?
A polyatomic ion is a group of atoms bonded together that carries a net positive or negative charge.
61
In the nomenclature of oxoanions, the suffix [...] represents the "regular" form.
-ate
62
In oxyanion nomenclature, what does the prefix "per-" combined with the suffix "-ate" indicate?
"Per-...-ate" indicates an oxyanion that has one more oxygen atom than the corresponding "-ate" ion.
63
What are the primary practical uses and function of the hypochlorite ion (ClO⁻)?
Hypochlorite is the active ingredient in bleach and kills bacteria and viruses, especially in hospitals.
64
According to the text, what is a base?
A base is a substance that releases hydroxide ions (OH⁻) when dissolved in water.
65
What is the naming strategy for binary molecular compounds regarding prefixes and endings for the first and second elements?
The first element takes a prefix for its subscript (omitted if 1) plus its element name. The second element takes a prefix for its subscript plus the element name ending in "-ide".
66
When naming acids derived from polyatomic anions, an anion ending in "-ate" becomes [], while an anion ending in "-ite" becomes [].
An anion ending in "-ate" becomes an "-ic acid", and an anion ending in "-ite" becomes an "-ous acid".
67
When naming metal cations that do not have a fixed charge, how is the charge specified in the name?
The metal's charge is specified using Roman numerals in parentheses following the metal name.
68
How is an acid classified and represented according to the compound summary chart?
An acid is defined as a hydrogen ion combined with an anion in aqueous solution: (H⁺ + anion), aq.
69
Which specific metals and polyatomic ion are explicitly listed as cations having a fixed charge?
Alkali metals, alkaline earth metals, Al^3+, Zn^2+, Cd^2+, Ag^+, and the polyatomic ion NH4^+.
70
How are polyatomic anions named when forming ionic compounds?
Use the standard name of the polyatomic anion directly without altering its ending to "-ide".
71
What naming rule is applied to HBr in the gaseous state, HBr(g)?
It follows the rules for naming binary molecules without prefixes for either element, giving the name hydrogen bromide.