topic 1 - atomic structure and the periodic table Flashcards
1
Q
What is the arrangement of elements in the periodic table based on?
A
Elements in the periodic table are arranged in order of increasing atomic proton number.
2
Q
How are elements arranged in groups within the periodic table?
A
Elements with similar properties are arranged in columns known as groups. Elements in the same group have the same number of electrons in their outer shell.
3
Q
What are the common properties of elements in the same group of the periodic table?
A
Elements in the same group exhibit similar chemical properties due to having the same number of electrons in their outer shell.
4
Q
Who created the early periodic table and what was his primary contribution?
A
John Newlands created an early periodic table and proposed the ‘law of octaves’ noting that similar properties occurred every eighth element.
5
Q
What limitation did John Newlands’ periodic table have?
A
Newlands’ periodic table broke down after calcium as its grouping did not hold for all subsequent elements.
6
Q
How did Dmitri Mendeleev revise the periodic table compared to John Newlands?
A
Dmitri Mendeleev ordered his periodic table by atomic mass and changed the order of some elements based on their properties rather than strictly following atomic mass.
7
Q
What was a significant feature of Mendeleev’s periodic table?
A
Mendeleev’s periodic table left gaps for elements that he predicted had not yet been discovered demonstrating foresight in the development of the table.
8
Q
Why is the periodic table called ‘periodic’?
A
The periodic table is referred to as ‘periodic’ because similar properties of elements occur at regular intervals.
9
Q
What is the significance of the atomic proton number in the periodic table?
A
The atomic proton number is significant because it determines the element’s position on the periodic table and its identity.
10
Q
What does the term ‘group’ refer to in the context of the periodic table?
A
A ‘group’ in the periodic table refers to a vertical column where elements share similar characteristics due to their same number of outer shell electrons.
11
Q
What is the significance of the modern periodic table in relation to Mendeleev’s predictions?
A
The modern periodic table filled the gaps left by Mendeleev’s original table through the discovery of elements with properties that matched his predictions.
12
Q
How did knowledge of isotopes affect the arrangement of elements in the periodic table?
A
The knowledge of isotopes provided explanations for why arranging elements by atomic weights alone resulted in inaccuracies as isotopes can have the same atomic weight but different atomic structures.
13
Q
What were the key particles discovered in the early 20th century that changed how elements were ordered?
A
The discovery of electrons protons and neutrons allowed for elements to be ordered by atomic proton number instead of atomic weight leading to a more accurate grouping of elements.
14
Q
How are metals and non-metals distinguished in the periodic table?
A
Metals are elements that primarily form positive ions and are predominantly found on the left and bottom of the periodic table while non-metals do not form positive ions and are located on the right and top.
15
Q
What are the characteristics of Group 1 elements also known as alkali metals?
A
Alkali metals have one electron in their outer shell which leads to unique properties such as vigorous reactions with water to form alkaline solutions and hydrogen and they form oxides when reacting with oxygen.
16
Q
What is the reaction of alkali metals with water?
A
Alkali metals react vigorously with water to produce an alkaline solution and hydrogen gas.
17
Q
What happens when alkali metals react with oxygen?
A
When alkali metals react with oxygen they form metal oxides.
18
Q
Where are metals generally located in the periodic table?
A
Most metals are found on the left and towards the bottom of the periodic table.
19
Q
Where are non-metals generally located in the periodic table?
A
Non-metals are primarily located towards the right and the top of the periodic table.
20
Q
What defines a metal in terms of ion formation?
A
A metal is defined by its ability to react and form positive ions.
21
Q
What defines a non-metal in terms of ion formation?
A
A non-metal is characterized by its lack of ability to form positive ions.
22
Q
What color precipitate is formed when chlorine reacts with elements in the group?
A
Chlorine reacts with elements in the group to form a white precipitate.
23
Q
How does the reactivity of alkali metals change as you move down the group?
A
The reactivity of alkali metals increases as you move down the group.
24
Q
What is the reaction of lithium with oxygen?
A
Lithium burns with a strongly red-tinged flame and produces a white solid upon reacting with oxygen.
25
Describe the reaction of lithium with water.
When lithium reacts with water it fizzes steadily gradually disappears and produces a white powder that settles on the sides of the container.
26
What flame color does sodium produce when it burns?
Sodium burns with a strong orange flame.
27
What happens when sodium reacts with water?
Sodium fizzes rapidly melts into a ball and disappears quickly releasing a white solid that produces clouds and settles on the sides of the container.
28
What is the characteristic flame color exhibited by potassium during combustion?
Potassium produces a lilac flame when it burns.
29
How does the reactivity of potassium compare to sodium?
Potassium reacts even more vigorously than sodium with large pieces producing a lilac flame and smaller pieces igniting with sparks and a lilac flame disappearing very quickly.
30
What is the electron configuration of noble gases?
Noble gases have 8 electrons in their outer shell except for helium which has 2.
31
Why are noble gases unreactive?
Noble gases are unreactive because they have full outer shells which makes them stable and unlikely to form molecules.
32
What is the significance of the arrangement of electrons in an atom?
The arrangement of electrons determines an element's reactivity as elements strive to achieve a full outer shell of electrons. A full outer shell often consisting of 8 electrons (with some exceptions) represents a stable electronic configuration.
33
How does the boiling point of noble gases change with relative atomic mass?
The boiling points of the noble gases increase with increasing relative atomic mass as you move down the group. This is due to increased London dispersion forces caused by the greater number of electrons and larger electron cloud in heavier noble gases.
34
What are halogens and what is unique about their electron configuration?
Halogens are elements in Group 7 of the periodic table characterized by having seven electrons in their outer shell. This configuration leads to similar chemical properties and reactivity among halogens.
35
How do halogens exist in nature?
Halogens exist as diatomic molecules meaning they are found as pairs of atoms. For example chlorine exists as Cl2.
36
What type of compounds do halogens form when they react with metals?
When halogens react with metals they form ionic compounds. In these compounds the halide ion carries a -1 charge due to the gain of one electron.
37
How do halogens react with non-metals?
Halogens react with nonmetals to form covalent compounds where there is a shared pair of electrons between the participating nonmetal atoms.
38
What trends are observed in relative molecular mass melting point and boiling point among halogens as you go down the group?
As you move down Group 7 (the halogens) relative molecular mass melting point and boiling point all increase.
39
How does reactivity change among halogens as you go down the group?
Reactivity decreases down the group due to the increase in the number of electron shells. A larger atomic radius means the nucleus exerts a weaker attraction on additional electrons making it harder for the element to gain an extra electron to achieve a full outer shell.
40
What does it mean for a more reactive halogen to displace a less reactive one?
A more reactive halogen from higher up in Group 7 can displace a less reactive halogen from a compound. This occurs because the more reactive halogen can more easily attract and gain an additional electron to achieve a full outer shell.
41
Why do halogens react by gaining an electron?
Halogens react by gaining an electron to increase the number of electrons in their outer shell from 7 to 8 thereby achieving a full and stable electronic configuration.
42
Describe the relationship between the number of electron shells and how a halogen attracts electrons from other atoms.
As you move down the group of halogens the number of shells of electrons increases resulting in a larger atomic radius. This leads to a decreased ability to attract electrons from other atoms since the outer electrons are further from the nucleus.
43
What occurs when chlorine gas is bubbled through a solution of potassium bromide?
Chlorine gas will react with potassium bromide displacing bromine and producing potassium chloride.
44
What is the chemical reaction when chlorine displaces bromine in potassium bromide solution?
Cl2 (g) + 2 KBr (aq) -> 2 KCl (aq) + Br2 (g) . This indicates that chlorine being more reactive displaces bromine from its salt.
45
Explain the reactivity series in relation to halogens. Why does chlorine displace bromine?
The reactivity series ranks halogens by their ability to gain electrons. Chlorine is higher than bromine in this series meaning it is a stronger oxidizing agent and can displace bromine from bromide solutions.
46
What are the products formed when chlorine is bubbled through a potassium bromide solution?
The products formed are potassium chloride (KCl) and bromine (Br2).
47
What type of reaction occurs when chlorine displaces bromine from potassium bromide?
This is a single displacement (or single replacement) reaction where one element displaces another in a compound.
48
List the ionic species present in a solution of potassium bromide (KBr) before chlorine is introduced.
In a solution of potassium bromide the ionic species present are potassium ions (K+) and bromide ions (Br-).
49
What happens to the potassium ions and bromide ions during the reaction with chlorine?
The potassium ions remain in the solution as potassium chloride is formed while bromide ions are replaced by chloride ions as chlorine gas displaces bromine.
50
Identify the role of chlorine in the reaction with potassium bromide.
Chlorine acts as an oxidizing agent facilitating the displacement of bromine and thus being reduced in the process.
51
How can the displacement of bromine by chlorine be visually confirmed in a laboratory setting?
The displacement can be visually confirmed by observing the color change; bromine is a brownish color and upon displacement the solution will become lighter as bromine is released as a gas.
52
What is the significance of reactivity in halogens in the context of chemical reactions?
Reactivity among halogens determines their ability to participate in displacement reactions. More reactive halogens (like chlorine) can displace less reactive halogens (like bromine) from their compounds.
53
What are atoms and their significance in chemistry?
Atoms are the smallest part of an element that can exist. They make up all substances and are fundamental to understanding chemical structures and reactions.
54
What is the symbol for sodium and what does it represent?
The symbol for sodium is Na. It represents an atom of the element sodium.
55
How are compounds formed?
Compounds are formed from elements through chemical reactions which involve the formation of one or more new substances and often involve an energy change.
56
What defines a compound in terms of elements?
A compound contains two or more elements that are chemically combined in fixed proportions.
57
How can compounds be represented?
Compounds can be represented by chemical formulae using the symbols of the atoms from which they were formed for example HCl represents a compound containing 1 atom of hydrogen and 1 atom of chlorine per molecule.
58
How can compounds be separated?
Compounds can only be separated into their constituent elements by chemical reactions.
59
What constitutes a mixture?
A mixture consists of two or more elements or compounds that are not chemically combined. This means they retain their individual properties.
60
What are chemical symbols and give an example?
Chemical symbols represent an atom of an element. For example H represents an atom of hydrogen.
61
What is relative atomic mass and why is it important?
Relative atomic mass is a measure of the mass of an atom compared to one twelfth of the mass of a carbon-12 atom. It is important for understanding the mass relationships in chemical reactions.
62
What is an isotope?
Isotopes are atoms of the same element that have the same number of protons but different numbers of neutrons resulting in different atomic masses.
63
What role do chemical reactions play in the formation of compounds?
Chemical reactions are essential for the formation of compounds as they bring together different elements or compounds to form new substances.
64
What happens to the properties of elements in a compound?
When elements form compounds they typically lose their individual properties and exhibit properties that are different from the elements they were made from.
65
Explain the energy changes involved in chemical reactions.
Chemical reactions often involve energy changes such as the release of energy (exothermic reactions) or the absorption of energy (endothermic reactions) which can be detected through temperature changes.
66
What is the difference between a compound and a mixture?
A compound is formed when two or more elements are chemically bonded together and cannot be separated by physical means while a mixture is a combination of two or more substances that are not chemically bonded and can be separated by physical means.
67
What is the significance of fixed proportions in compounds?
Fixed proportions in compounds indicate that specific amounts of each element combine in a definite ratio which is crucial for predicting the behavior of the compound in chemical reactions.
68
What is a chemical formula and what information does it convey?
A chemical formula represents the elements in a compound and the number of atoms of each element in that compound conveying important information about its composition.
69
What is meant by 'energy change' in a chemical reaction?
'Energy change' refers to the change in energy that occurs during a chemical reaction which can result in heat being released or absorbed and is a key factor in determining the reaction's progress and outcome.
70
What are the characteristics of a mixture?
A mixture consists of two or more substances combined together where the chemical properties of each substance remain unchanged. Mixtures can be separated using physical processes.
71
What are physical processes that can be used to separate mixtures?
Mixtures can be separated by filtration crystallisation simple distillation fractional distillation and chromatography.
72
What is the difference between a mixture and a compound?
A mixture allows the components to retain their individual properties and can be separated by physical means whereas a compound is a substance formed when two or more elements bond chemically resulting in new properties.
73
What was the early model of the atom?
The earliest theory posited that atoms were tiny indivisible spheres.
74
What significance did the discovery of the electron have on atomic theory?
The discovery of the electron led to the 'plum pudding model' proposing that an atom is a sphere of positive charge with negatively charged electrons embedded within.
75
Describe the alpha particle scattering experiment.
In the alpha particle scattering experiment a beam of alpha particles was directed at thin gold foil to study its structure. Detectors recorded how the particles passed through the foil.
76
What were the conclusions from the alpha particle scattering experiment?
The experiment concluded that the mass of an atom is concentrated in a small nucleus at its center which is positively charged.
77
What phenomena were observed during the alpha particle scattering experiment?
Some alpha particles passed straight through the gold foil while others were deflected at various angles with some even rebounding back indicating the presence of a dense positively charged nucleus.
78
What does 'scattering' mean in the context of the alpha particle experiment?
'Scattering' refers to the deflection of alpha particles at various angles when they encounter the positively charged nucleus of the atoms in the gold foil.
79
How did the plum pudding model differ from the nuclear model of the atom?
The plum pudding model depicted the atom as a uniform distribution of positive charge with electrons scattered throughout while the nuclear model introduced the concept of a dense nucleus at the center containing most of the atom's mass.
80
What is the primary concept suggested by Neil Bohr regarding electron behavior in atoms?
Neil Bohr suggested that electrons orbit the nucleus at specific distances a concept supported by experimental data.
81
What was discovered later about the positive charge of atomic nuclei?
Later experiments showed that the positive charge of any nucleus could be subdivided into a whole number of smaller particles with each particle having the same amount of positive charge known as protons.
82
Who provided evidence for the existence of neutrons in the nucleus?
James Chadwick provided evidence to demonstrate the existence of neutrons within the atomic nucleus.
83
How long had the idea of neutrons in the nucleus been accepted before Chadwick's work?
The idea of neutrons in the nucleus had been accepted for about 20 years before James Chadwick provided evidence for their existence.
84
What is the definition of atomic number?
The atomic number is the number of protons in an atom of an element. All atoms of a particular element have the same number of protons while atoms of different elements have different numbers of protons.
85
What are the relative electrical charges of protons neutrons and electrons?
The relative charges are as follows: proton = +1 neutron = 0 electron = -1.
86
What is the overall charge of an atom and how is it determined?
An atom has an overall charge of 0 which is determined by the equality of the number of protons and the number of electrons in the atom.
87
What are the typical sizes of atoms and atomic nuclei?
Atoms are very small with a radius of about 0.1 nanometers (nm) while the radius of a nucleus is even smaller.
88
Explain the significance of protons in relation to the identity of an element.
Protons are significant because they define the atomic number of an element determining the element's identity. All atoms of that element contain the same number of protons.
89
What is the relationship between protons neutrons and the overall charge of the atom?
The overall charge of an atom is neutral (0) when the number of protons (positive charge) is equal to the number of electrons (negative charge). The neutrons contribute no charge.
90
What is the relative mass of a proton?
The relative mass of a proton is 1.
91
What is the relative mass of a neutron?
The relative mass of a neutron is 1.
92
What is the relative mass of an electron?
The relative mass of an electron is very small approximately 1/1836 of a proton.
93
Define mass number.
Mass number is the sum of the number of protons and neutrons in an atom.
94
What are isotopes?
Isotopes are atoms of the same element that have different numbers of neutrons.
95
How is relative atomic mass defined?
Relative atomic mass is an average value that takes into account the abundance of the various isotopes of that element.
96
Example: Carbon has two isotopes carbon-14 (abundance 20) and carbon-12 (abundance 80). Calculate the relative atomic mass of carbon.
Relative atomic mass = (Isotope 1 mass x abundance + Isotope 2 mass x abundance) / 100. For carbon: (14 x 20 + 12 x 80) / 100 = (280 + 960) / 100 = 1240 / 100 = 12.4.
97
What is electronic structure?
The electronic structure of an atom describes how many electrons are in each energy shell with the rule that electrons occupy the lowest available energy levels (the shells closest to the nucleus) first.
98
Describe the electronic structure of sodium.
The electronic structure of sodium indicates that it has 2 electrons in the first shell (closest to the nucleus) and 8 electrons in the second shell.
99
What is the significance of energy levels in electronic structure?
Energy levels determine the arrangement of electrons in an atom affecting chemical properties and reactions. Electrons fill the lowest energy levels first before moving to higher ones.
100
What does the periodic table indicate about isotopes of elements?
The periodic table usually lists the most stable or abundant isotope of an element but indicates the atomic mass which is a weighted average of all isotopes based on their natural abundance.
101
What is the mathematical formula used to calculate the relative atomic mass based on isotopes?
Relative atomic mass = (Sum of all (mass of isotope x abundance of isotope)) / 100.
102
What is the electronic configuration for the shell structure of an element with atomic number 11?
The electronic configuration for an element with atomic number 11 (Sodium) is 2 8 1 which means it has 2 electrons in the first shell 8 in the second shell and 1 electron in the third shell.
103
What does the notation '2 8 1' indicate in terms of electron shells?
The notation '2 8 1' indicates the distribution of electrons among the electron shells: 2 electrons in the first shell 8 electrons in the second shell and 1 electron in the third shell.
104
How many electrons can the first shell hold?
The first shell can hold a maximum of 2 electrons.
105
How many electrons can the second shell hold?
The second shell can hold a maximum of 8 electrons.
106
How many electrons can the third shell hold?
The third shell can hold a maximum of 18 electrons but in many cases it holds 8 electrons as it is the outer shell for many elements in the second period.
107
What information can be inferred from the electronic configuration 2 8 1?
From the electronic configuration 2 8 1 one can infer that the element is likely to lose its one outermost electron during a chemical reaction (since it has 1 electron in the outer shell) making it more reactive and giving it characteristics associated with alkali metals.
108
Which group in the periodic table does the element with electronic configuration 2 8 1 belong to?
The element with electronic configuration 2 8 1 belongs to Group 1 of the periodic table which includes alkali metals.
109
What is the maximum number of electrons in the nth shell? In general terms what is the formula?
The maximum number of electrons in the nth shell can be calculated using the formula 2n². For example the 1st shell can hold 2(1)² = 2 electrons the 2nd shell can hold 2(2)² = 8 electrons and the 3rd shell can hold 2(3)² = 18 electrons.
110
How does adding more electrons affect the electronic structure as you move down the groups of the periodic table?
As you move down the groups of the periodic table additional electron shells are added which expands the electronic structure and contributes to the size of the atom and its reactivity.
111
What is the significance of electron shells in determining the chemical properties of elements?
The arrangement of electrons in shells influences the element's reactivity bonding behavior and type of ions it may form. Elements with similar arrangements of electrons tend to exhibit similar chemical properties.
112
Can you provide a brief overview of the periodic table groups based on their electron configurations?
Group 1 (alkali metals) has 1 electron in the outermost shell; Group 2 (alkaline earth metals) has 2 electrons; Groups 13-18 follow specific filling rules up to the p-block. Transition metals (Groups 3-12) have d-electrons impacting their properties and coordination chemistry.
113
What are the general physical properties of transition metals compared to group 1 elements?
Transition metals are harder stronger have higher melting points (except for mercury) and have higher densities compared to group 1 elements.
114
How reactive are transition metals compared to group 1 metals?
Transition metals are much less reactive and do not react as vigorously with oxygen or water as group 1 metals.
115
List the transition elements mentioned in the notes.
The transition elements mentioned are chromium manganese iron cobalt nickel and copper.
116
What are the general properties of chromium in terms of its physical and chemical characteristics?
Chromium is a hard brittle and very brittle metal that is difficult to fuse but easy to oxidize. It has multiple ion charges (2 3 4 5 and 6) and forms colored compounds.
117
Describe the properties of manganese.
Manganese is a hard and brittle metal has a high melting point can have ion charges of 2 3 4 5 and 6 and is known for forming colored compounds.
118
What is iron's typical property as a transition metal?
Iron is generally strong rusts easily in air is a good conductor of heat and electricity has ion charges of 2 3 4 5 and 6 and forms colored compounds.
119
Explain the properties of cobalt as a transition metal.
Cobalt is hard malleable and ductile with ion charges of 2 3 4 5 and 6. It can also easily form colored compounds.
120
What are the characteristics of nickel?
Nickel is hard malleable and ductile and has good conductivity. It can have ion charges of 2 3 4 5 and 6 and forms colored compounds.
121
Describe copper's properties as a transition metal.
Copper is highly ductile and conductive is malleable and soft and has ion charges of 2 3 4 5 and 6. It also forms colored compounds.
122
What are the unique characteristics of transition metals regarding their ions?
Transition metals typically have ions with many different charges.
123
What is the importance of transition metals in chemical reactions?
Transition metals are useful as catalysts in various chemical reactions.
124
How do the melting points of transition metals compare to those of group 1 metals?
Transition metals generally have higher melting points compared to group 1 metals with the exception of mercury which has a lower melting point.
125
What distinguishes the conductivity of transition metals?
Transition metals are known for being good conductors of heat and electricity due to their metallic bonding and free-moving electrons.
126
What are the common colors associated with transition metal compounds with a +2 charge?
Compounds with a +2 charge from transition metals typically exhibit colors such as blue (e.g. Cu^2+) green (e.g. Ni^2+) and pink (e.g. Co^2+). Different metal cations lead to different colors due to the variation in d-orbitals.
127
What are the common colors associated with transition metal compounds with a +3 charge?
Transition metal compounds with a +3 charge often show colors such as yellow (e.g. Fe^3+) brown (e.g. Cr^3+) and green (e.g. Co^3+). The specific color depends on the ligand field and the electronic transitions between d-orbitals.
128
What colors are associated with transition metal compounds that have a +4 charge?
Transition metal compounds with a +4 charge can appear in colors like blue (e.g. Mn^4+) and green (e.g. Ti^4+). Like other oxidation states the precise color will depend on the surrounding ligands.
129
What colors can be associated with transition metal compounds having a +6 charge?
Compounds with a +6 charge often show yellow or orange colors such as in the case of CrO_4^2- (chromate) and Cr_2O_7^2- (dichromate).
130
What colors are typical for transition metal compounds with a +7 charge?
Transition metal compounds with a +7 charge like permanganate (MnO_4^-) typically exhibit a deep purple color.
131
What is the balanced chemical equation for the decomposition of hydrogen peroxide (H2O2)?
The balanced equation for the decomposition of hydrogen peroxide is: 2H_2O_2 → 2H_2O + O_2.
132
What is the Haber process and what is its balanced equation?
The Haber process is used to synthesize ammonia (NH_3) from nitrogen (N_2) and hydrogen (H_2) gases. The balanced equation for the reaction is: N_2 + 3H_2 ⇌ 2NH_3.
133
How is hydrogen used in the manufacturing of margarine?
Hydrogen is used in the manufacture of margarine by adding H_2 to the double bonds of unsaturated fats in a process known as hydrogenation which converts liquid oils into solid or semi-solid fats.
134
What role do transition metals play as catalysts?
Transition metals serve as catalysts by providing an alternative reaction pathway with a lower activation energy. They often participate in the formation of intermediates which accelerates the overall reaction without being consumed.
135
Give an example of a transition metal catalyst used in the decomposition of hydrogen peroxide.
An example of a transition metal catalyst used in the decomposition of hydrogen peroxide is manganese dioxide (MnO2) which accelerates the breaking down of hydrogen peroxide into water and oxygen.
136
What are ligands and why are they important in transition metal chemistry?
Ligands are atoms ions or molecules that can donate a pair of electrons to a transition metal to form a coordinate bond. They influence the properties of transition metal complexes including stability color reactivity and magnetic behavior.
137
Describe the significance of the color of transition metal compounds in analytical chemistry.
The color of transition metal compounds is significant in analytical chemistry because it can be used for qualitative analysis (identifying the presence of certain metal ions) and quantitative analysis (determining the concentration of metal ions in solutions using colorimetric methods).
