Periodic Table And Periodicity Of Properties Flashcards
1
Q
What was the number of known elements in the year 1800?
A
Thirty-four (34) elements were known.
2
Q
What was the number of known elements in the year 1870?
A
The number increased to almost double.
3
Q
How many elements are known today?
A
There are 118 known elements today.
4
Q
How many elements are naturally occurring on Earth?
A
92 elements are naturally occurring on Earth.
5
Q
What are artificially prepared elements?
A
The elements beyond 92 are artificially prepared.
6
Q
Why was it initially easy to study elements individually?
A
The number of elements was limited, so it was easy for chemists to study them individually.
7
Q
Why did it become difficult to study elements as time passed?
A
As the number of elements increased, it became difficult to study each element individually.
8
Q
Who attempted to classify elements systematically before Mendeleev?
A
Chemists such as Lavoisier (1787), Newlands (1864), and others attempted to classify the elements systematically.
9
Q
Who made the most successful classification of elements?
A
Dmitri Mendeleev (1869) made the most successful classification based on atomic masses.
10
Q
What did Mendeleev base his classification on?
A
Mendeleev classified elements based on their atomic masses.
11
Q
Who first divided elements into metals and non-metals?
A
Elements were initially divided into metals and non-metals.
12
Q
What did J.W. Dobereiner do in 1817?
A
J.W. Dobereiner classified chemically similar elements into groups of three, called triads, based on their atomic masses.
13
Q
What is a triad in chemistry?
A
A triad is a group of three elements with chemically similar properties and the atomic weight of the middle element being the arithmetic mean of the other two.
14
Q
Who discovered the law of octaves?
A
J. Newlands discovered the law of octaves in 1864.
15
Q
What does the law of octaves state?
A
The law of octaves states that every eighth element has properties similar to the first element in the series.
16
Q
What did Newlands classify elements into?
A
Newlands classified elements into groups of seven.
17
Q
Why did Newlands’ law of octaves fail?
A
Newlands’ law of octaves failed to classify all the elements due to newly discovered elements that did not fit the pattern.
18
Q
Who developed a similar arrangement of elements as Mendeleev?
A
Lother Meyer in Germany and Dmitri Mendeleev in Russia independently developed similar arrangements.
19
Q
What did Lother Meyer plot against atomic masses?
A
Lother Meyer plotted atomic volumes (densities) against atomic masses.
20
Q
What did Mendeleev predict based on his periodic table?
A
Mendeleev predicted the properties of undiscovered elements accurately.
21
Q
What was the main flaw in Mendeleev’s classification?
A
Mendeleev’s classification was based on atomic mass, not atomic number.
22
Q
Why did atomic number become more important than atomic mass?
A
With the discovery of atomic structure, it became clear that properties depended on the number and arrangement of electrons, not atomic mass.
23
Q
Who proposed the modern periodic table?
A
The modern periodic table was proposed by Henry Gwyn Jeffreys Moseley, an English physicist.
24
Q
What is the basis of the modern periodic table?
A
The modern periodic table is based on the atomic number.
25
What does the modern periodic law state?
The modern periodic law states that the physical and chemical properties of elements are periodic functions of their atomic number.
26
What are the two main divisions of the periodic table?
The periodic table is divided into eight vertical columns (groups/families) and seven horizontal rows (periods).
27
How are periods numbered in the periodic table?
Periods are numbered from 1 to 7 in the periodic table.
28
What is the main characteristic of elements within the same period?
Elements in the same period have the same number of electronic shells.
29
How many shells are present in elements of the first, second, and third periods?
The first period has 1 shell, the second period has 2 shells, and the third period has 3 shells.
30
What is the rarest naturally occurring element in the Earth's crust?
Astatine is the rarest naturally occurring element in the Earth's crust.
31
What is the element symbol for Sodium?
The symbol for Sodium is Na.
32
What does 'J' refer to in the periodic table's context?
The letter 'J' does not appear in the periodic table.
33
Who is credited with the discovery of the periodic table's periodicity based on atomic number?
Henry Gwyn Jeffreys Moseley is credited with discovering the periodicity of elements based on their atomic number.
34
Which element in the Earth's crust contains around 2g of its form?
The element that appears to contain about 2g in the Earth's crust is Astatine.
35
How many periods are there in the modern periodic table?
There are seven periods in the modern periodic table.
36
How many periods are there in the periodic table?
7 periods
37
Which period contains only two elements?
The first period, hydrogen (H) and helium (He)
38
How many elements are in periods 2 and 3?
8 elements
39
How many elements are in periods 4 and 5?
18 elements
40
In periods 4 and 5, how are the elements classified?
8 representative elements and 10 transition elements
41
In the 6th period, how many representative elements are there?
8 representative elements
42
In the 6th period, how many transition elements are there?
10 transition elements
43
How many Lanthanide elements are in the 6th period?
14 Lanthanide elements
44
In the 7th period, how many Actinide elements are there?
14 Actinide elements
45
How many elements are in the Lanthanide series?
14 elements
46
Where are the Lanthanide series elements placed in the periodic table?
Below the main table
47
How many elements are in the Actinide series?
14 elements
48
Where are the Actinide series elements placed in the periodic table?
Below the Lanthanide series
49
What are the vertical columns in the periodic table called?
Groups
50
What do elements in the same group have in common?
They have the same number of valence electrons
51
How do the chemical properties of elements in the same group compare?
They show similar chemical properties due to the same number of valence electrons.
52
Which of the following are Group 1 elements?
Lithium (Li), Sodium (Na), Potassium (K)
53
What is a characteristic of Group 1 elements?
They are very reactive, electropositive, and show metallic character.
54
As the group number increases, what happens to the number of valence electrons?
It increases.
55
How are representative elements defined?
They are all s-block and p-block elements.
56
As you move from left to right across a period, what happens to metallic properties?
Metallic properties decrease.
57
Why is the periodic table incomplete?
New elements are still being discovered and will be added over time.
58
What is the first element in the periodic table?
Hydrogen (H)
59
Which group of elements is known for having one valence electron?
Group I (Alkali metals)
60
__ is the most reactive element in the periodic table.
Fluorine (F)
61
True or False: All elements in the same period have the same number of electron shells.
True
62
Which group is known for its chemical inertness?
Group VIII (Noble gases)
63
What is the position of the first element of the second period in the periodic table?
Hydrogen (H)
64
True or False: All elements in the same group have the same number of valence electrons.
True
65
What is the general characteristic of transition metals?
They have variable valency.
66
Which block elements are located in groups I to VII?
P-block elements
67
__ is the last element of the Lanthanide series.
Lutetium (Lu)
68
Which of the following is the first coinage metal?
Copper (Cu)
69
True or False: The noble gases are highly reactive due to their incomplete valence shells.
False
70
How many elements are in the Actinide series?
14
71
What is the first alkaline earth metal?
Beryllium (Be)
72
In which period are Lanthanide series elements found?
Period 6
73
__ is the most electronegative element.
Fluorine (F)
74
What percentage of Earth's atmosphere is made up of Nitrogen?
0.78084
75
True or False: Oxygen concentrations below 16% are considered unsafe for humans.
True
76
Which element is the first transition metal in the periodic table?
Scandium (Sc)
77
How many periods are there in the periodic table?
7
78
True or False: The atomic number increases as you move from left to right across a period.
True
79
What is the characteristic of elements in the same group of the periodic table?
They have the same number of valence electrons.
80
__ is the second noble gas in the periodic table.
Neon (Ne)
81
Which element is the first element in the noble gas group?
Helium (He)
82
True or False: Transition metals are found in the s-block of the periodic table.
False
83
Which of the following elements is a representative element?
Oxygen (O)
84
__ is the first actinide element.
Thorium (Th)
85
What is the most reactive element?
Fluorine (F)
86
Which gas is found in large quantities in Earth's atmosphere?
Nitrogen (N)
87
True or False: Lanthanide elements are found below the main periodic table.
True
88
What is the last element of the second period of the periodic table?
Neon (Ne)
89
To which group does the element Potassium belong?
Group I (Alkali metals)
90
To which period does the element Arsenic belong?
Period 4
91
To which group does the element Titanium belong?
Group IV
92
State whether Cesium is a metal or non-metal.
Metal
93
State whether Boron is a metal or non-metal.
Non-metal
94
State whether Selenium is a metal or non-metal.
Non-metal
95
State whether Phosphorous is a metal or non-metal.
Non-metal
96
State whether Astatine is a metal or non-metal.
Non-metal
97
State whether Osmium is a metal or non-metal.
Metal
98
How many shells and valence electrons does Calcium have?
2 shells, 2 valence electrons
99
Element X is located in period III, group II of the periodic table, deduce its electronic configuration.
2, 8, 2
100
True or False: All elements in the same group have similar chemical properties.
True
101
True or False: The periodicity of properties in the periodic table refers to the repeating patterns of physical and chemical properties.
True
102
What is atomic radius?
The distance between the nucleus and the valence shell of an atom.
103
What is the atomic radius directly proportional to?
The number of electron shells.
104
True or False: Atomic size varies when atoms combine with other atoms.
True
105
Fill in the blank: The atomic radius is measured in either nanometers (nm) or ___.
Picometers (pm)
106
What is the general trend of atomic radius as you move across a period from left to right?
It decreases.
107
How does the atomic radius change as you go down a group?
It increases.
108
Which of the following is true regarding atomic radius?
Atomic radius increases as you move down a group.
109
Which of the following is the trend of atomic radius in groups?
Atomic radius increases from top to bottom in a group
110
What causes the increase in atomic radius as you move down a group?
The addition of new shells and the shielding effect of electrons
111
Atomic radius decreases as you move from left to right across a period. (True or False?)
True
112
What is the reason for the decrease in atomic radius across a period?
Increase in the number of protons and electrons, leading to a stronger nuclear pull
113
Fill in the blank: The atomic radius of Cs is ___.
2.35 Å
114
What is the atomic radius of Na?
1.23 Å
115
The atomic radius of F is greater than that of Cl. (True or False?)
False
116
Fill in the blank: The atomic radius of Mg is ___.
1.36 Å
117
Which of the following elements has the smallest atomic radius?
He
118
Fill in the blank: The covalent radius is one half of the distance between the nuclei of two similar atoms in a molecule. The formula is ___
Covalent radius = d/2
119
True or False: The bond distance between two atoms A and B is the average of the lengths A-A and B-B.
True
120
What is the covalent radius of H?
0.37 Å
121
What does the covalent radius measure?
The half distance between the nuclei of two similar atoms in a molecule
122
What is the ionization energy?
The minimum energy required to remove the valence electron from the outermost shell of a gaseous atom
123
The ionization energy of sodium is higher than that of magnesium. (True or False?)
False
124
Fill in the blank: The first ionization energy of sodium is represented as Na -> Na+ + e-. The ionization energy of sodium is ___.
496 kJ/mol
125
What is the unit used to measure ionization energy?
kJ/mol
126
Fill in the blank: The process of ionization requires energy to completely remove an electron from an atom. This process is called ___.
Ionization
127
Which of the following elements has the highest ionization energy in Period 2?
Ne
128
Fill in the blank: The ionization energy of magnesium is represented as Mg -> Mg+ + e-. The ionization energy of magnesium is ___.
737 kJ/mol
129
Which factor does NOT affect the ionization energy of an atom?
Atomic mass
130
What is the ionization energy of magnesium's second ionization?
3272 kJ/mol
131
True or False: Ionization energy increases as you move across a period from left to right.
True
132
What causes ionization energy to increase across a period?
Increase in nuclear charge and decrease in atomic radius
133
What is the trend for ionization energy in groups?
Ionization energy decreases as you move down a group
134
Fill in the blank: The ionization energy of chlorine is higher than that of sulfur. (True or False?)
True
135
Which of the following elements has the smallest ionization energy in Period 3?
Na
136
What is the ionization energy of Na?
496 kJ/mol
137
Which of the following trends occurs for ionization potential in groups?
Ionization potential decreases as you move down a group
138
True or False: Elements at the top of a group have the lowest ionization potential.
False
139
What is the trend for ionization potential across a period?
Ionization potential increases from left to right across a period
140
Fill in the blank: The ionization potential is highest for elements on the extreme ___ of the period.
right
141
Which of the following elements has the largest ionization energy?
Se
142
True or False: Ionization energy increases as you move down a group.
False
143
Fill in the blank: The ionization potential of sodium is ___.
496 kJ/mol
144
What is the ionization energy of Magnesium?
738 kJ/mol
145
Which element in Period 2 has the highest ionization energy?
Ne
146
Fill in the blank: The ionization potential of potassium is ___.
419 kJ/mol
147
What trend is observed for ionization potential as we move from left to right across a period?
It increases because the atomic size decreases and nuclear charge increases
148
Which element in the following set has the smallest ionization energy? (K, Ga, Se)
K
149
True or False: The ionization energy increases as you move down a group.
False
150
Which of the following elements has the highest first ionization energy?
C
151
Fill in the blank: The ionization energy of chlorine is ___.
1251 kJ/mol
152
Which group of elements is more reactive, Group I or Group II?
Group I
153
Why are elements from Group I more reactive than elements from Group II?
Because Group I elements have lower ionization energy, making it easier to lose an electron
154
What is electron affinity?
The energy released when an electron is added to a gaseous atom to form an anion
155
True or False: Electron affinity is always a positive value.
False
156
Fill in the blank: The energy released when the first electron is added to an atom is called the ___ electron affinity.
First
157
What happens when the second electron is added to an atom?
Energy is absorbed due to electron-electron repulsion
158
Which of the following factors affect electron affinity?
Nuclear charge, atomic radius, shielding effect, and electronic configuration
159
Fill in the blank: Electron affinity generally ___ as you move across a period from left to right.
Increases
160
What happens to electron affinity as you move down a group in the periodic table?
It decreases
161
Which of the following elements has the highest electron affinity?
Cl
162
True or False: Atoms with larger atomic radii tend to have higher electron affinity values.
False
163
Fill in the blank: The electron affinity of chlorine is ___.
-328 kJ/mol
164
What is the electron affinity of sodium?
-52.9 kJ/mol
165
Which element has the lowest electron affinity in Period 2?
Be
166
True or False: The electron affinity of an element is measured in kJ/mol.
True
167
Fill in the blank: The electron affinity of rubidium is ___.
-46.9 kJ/mol
168
What trend is observed in electron affinity as you move across a period?
It increases due to the increase in nuclear charge and decrease in atomic radius
169
Which element has the highest electron affinity in Group 17?
Cl
170
Fill in the blank: The electron affinity of sulfur is ___.
-200 kJ/mol
171
What is the shielding effect?
The shielding effect is when inner electrons reduce the hold of the nucleus on the valence electrons, making them easier to remove.
172
True or False: The shielding effect is more effective in groups as we move down the periodic table.
True
173
Fill in the blank: The shielding effect in a group increases as we move from top to bottom due to the addition of new ___.
shells
174
How does shielding effect influence the removal of electrons?
It makes the removal of electrons from the outermost shell easier.
175
What happens to the shielding effect when moving from left to right in a period?
The shielding effect remains constant while the nuclear charge increases.
176
True or False: The shielding effect increases as you move across a period from left to right in the periodic table.
False
177
Which of the following factors affects electronegativity?
Nuclear charge, atomic radius, shielding effect, and electronic configuration.
178
Fill in the blank: Electronegativity is the ability of an atom to attract the shared pair of ___ in a covalent bond.
electrons
179
What happens to electronegativity as you move across a period from left to right?
It increases due to an increase in nuclear charge.
180
True or False: Electronegativity decreases as you move down a group because atomic radius increases.
True
181
Which of the following elements will have the highest electronegativity?
Fluorine
182
Fill in the blank: The bond between two atoms with the same electronegativity is called a ___ bond.
non-polar covalent
183
How does atomic radius affect electronegativity?
Greater atomic radius results in lower electronegativity.
184
What is the relationship between shielding effect and electronegativity?
As shielding effect increases, electronegativity decreases.
185
True or False: The more filled the electron orbitals are, the lower the electronegativity.
False
186
Which factor causes electronegativity to decrease as we move down a group?
Increase in atomic radius and shielding effect.
187
Fill in the blank: The ___ configuration makes it difficult for an atom to attract additional electrons, reducing its electronegativity.
completely filled or half-filled
188
Who developed the electronegativity scale based on bond energies of diatomic molecules?
Linus Pauling
189
What is the electronegativity of Fluorine on Pauling’s scale?
4
190
What is the least electronegative element, and what is its electronegativity value?
Cesium (Cs), 0.7
191
In a group, where is electronegativity the highest?
At the top of the group.
192
In a period, where is electronegativity the highest?
At the extreme right of the period.
193
What factors affect electronegativity?
Atomic volume, electron affinity, ionization potential, nature of combining atoms.
194
Why does electronegativity decrease down a group?
Due to the addition of shells, increase in atomic radius, and stronger shielding effect.
195
Why does electronegativity increase across a period?
Due to decreasing atomic size and increasing nuclear charge.
196
Which group of elements has the highest electronegativity values?
Halogens (Group 17).
197
Which set of elements has more similar chemical properties: (a) N, P, As or (b) Li, C, F?
Set (a) because they are in the same group.
198
Is sulfur more likely to be chemically similar to selenium (Se) or chlorine (Cl)?
Selenium (Se), because they are in the same group.
199
Who developed the Periodic Table by arranging elements in order of increasing atomic weights?
Mendeleev
200
What was the basis of the Old Periodic Law?
The physical and chemical properties of elements are a periodic function of their atomic weights.
201
What is the basis of the Modern Periodic Law?
The physical and chemical properties of elements are a periodic function of their atomic number.
202
How many groups and periods are in the Modern Periodic Table?
Eight groups and seven periods.
203
Fill in the blank: Elements in the periodic table are grouped into _, _, _, and _ blocks based on their outermost electrons and electronic configuration.
s, p, d, f
204
Which elements show variable valency?
Transition elements.
205
What is the Lanthanide series?
Elements that come after lanthanum in the 6th period.
206
What is the Actinide series?
Elements that come after actinium in the 7th period.
207
What are periodic properties?
Properties that repeat in all groups and periods after a certain interval.
208
What is atomic radius?
The distance between the nucleus and the valence shell of an atom.
209
What is ionization energy?
The minimum energy required to remove the valence electron from a gaseous atom to form a positive ion.
210
What is electron affinity?
The minimum amount of energy released when an electron is added to a gaseous atom.
211
True or False: Shielding effect is greater in atoms with a larger number of electrons.
True
212
What is the trend of electronegativity in the periodic table?
It increases across a period and decreases down a group.
