Quick Review Flashcards - Click to flip and test your knowledge!
Question
What is the basic unit of matter that consists of only one kind of atom and cannot be broken down into simpler substances?
Answer
An element.
Question
On what fundamental property did early chemists attempt to classify elements?
Answer
Atomic weight.
Question
According to Dobereiner's Law of Triads, how is the atomic weight of the middle element related to the other two elements?
Answer
It is the arithmetic mean of the atomic weights of the other two elements.
Question
In Dobereiner's classification, what specific term is used for a group of three chemically analogous elements?
Answer
A triad.
Question
Provide an example of a Dobereiner's triad using the elements Lithium ($7.0$) and Potassium ($39.0$).
Answer
Sodium ($23.0$).
Question
The classification system proposed by Newland in 1864 is known as the Law of _____.
Answer
Octaves
Question
According to Newland's Law of Octaves, which element in a series shows a repetition of the properties of the first element?
Answer
Every eighth element.
Question
What artistic analogy did Newland use to describe the repetition of elemental properties?
Answer
Notes on a musical scale.
Question
Beyond which element did Newland's Law of Octaves fail to hold true for heavy metals?
Answer
Potassium ($K$).
Question
State Mendeleeff's Periodic Law.
Answer
The physical and chemical properties of elements are periodic functions of their atomic weights.
Question
What term describes the phenomenon where elements with similar properties appear at regular intervals in the periodic table?
Answer
Periodicity of properties.
Question
How did Mendeleeff account for elements that had not yet been discovered while constructing his table?
Answer
He left gaps in the table.
Question
Which element was originally referred to by Mendeleeff as 'eka-silicon'?
Answer
Germanium.
Question
What was the name Mendeleeff gave to the undiscovered element that we now know as Scandium?
Answer
Eka-boron.
Question
Why was the position of isotopes considered a defect in Mendeleeff's periodic table?
Answer
Isotopes have different atomic weights but were forced into the same position based on chemical properties.
Question
In Mendeleeff's table, which anomalous pair of elements had a higher atomic weight element placed before a lower atomic weight element?
Answer
Cobalt ($wt. 58.9$) before Nickel ($wt. 58.6$).
Question
Who discovered in 1912 that atomic number is a more fundamental characteristic than atomic weight?
Answer
Moseley.
Question
State the Modern Periodic Law.
Answer
The physical and chemical properties of elements are periodic functions of their atomic numbers.
Question
What is the underlying reason for the periodicity of properties in the Modern Periodic Table?
Answer
The recurrence of similar electronic configurations after definite intervals of atomic number.
Question
Concept: Atomic radius
Answer
Definition: The distance between the centre of the nucleus and the outermost shell of an isolated atom.
Question
What is defined as the amount of energy required to remove an electron from the outermost shell of an isolated gaseous atom?
Answer
Ionisation potential.
Question
Term: Electron affinity
Answer
Definition: The amount of energy released when an atom in the gaseous state accepts an electron to form an anion.
Question
In the Modern Periodic Table, what are the seven horizontal rows of elements called?
Answer
Periods.
Question
In the Modern Periodic Table, what are the eighteen vertical columns called?
Answer
Groups.
Question
What information does the period number of an element provide about its atomic structure?
Answer
The number of electron shells in the atom.
Question
How many elements are present in Period 1 of the Modern Periodic Table?
Answer
Two ($H$ and $He$).
Question
Which periods in the Modern Periodic Table are classified as 'short periods' containing 8 elements each?
Answer
Period 2 and Period 3.
Question
Across a period from left to right, how does the metallic character of elements change?
Answer
It transitions from metallic to non-metallic character.
Question
What happens to the number of valence electrons as you move from left to right across a period?
Answer
The number of valence electrons increases by one for each subsequent element.
Question
For the main groups (1, 2, and 13-18), what does the group number signify regarding atomic structure?
Answer
The number of valence electrons.
Question
How does the number of electron shells change as you move down a subgroup?
Answer
The number of electron shells increases by one for each subsequent period.
Question
What is the common name for the elements in Group 1 [IA]?
Answer
Alkali metals.
Question
What is the common name for the elements in Group 2 [IIA]?
Answer
Alkaline earth metals.
Question
Which group of elements is known as the Halogens?
Answer
Group 17 [VIIA].
Question
Which group contains the Noble or inert gases?
Answer
Group 18 [0].
Question
Groups 3 to 12 in the periodic table consist of which type of elements?
Answer
Transition elements.
Question
What are the two horizontal rows of 14 elements each located at the bottom of the periodic table called?
Answer
Lanthanide and Actinide series (Inner transition elements).
Question
Which specific elements are referred to as 'Normal Elements'?
Answer
Elements in Groups 1, 2, and 13 to 17 where all shells are complete except the outermost.
Question
Term: Bridge elements
Answer
Definition: Elements of the second period that show a diagonal relationship in properties with elements of the third period in the next group.
Question
Why are alkali metals considered strong reducing agents?
Answer
They have one valence electron that can be easily removed (electron donors).
Question
What is the valency of elements belonging to the Alkaline Earth Metals group?
Answer
Two (divalent).
Question
What does the word 'Halogen' literally mean?
Answer
Salt producer.
Question
Why are Halogens classified as strong oxidising agents?
Answer
They have seven valence electrons and readily accept one electron to complete their octet (electron acceptors).
Question
Which halogen is the most reactive and most abundant in nature?
Answer
Fluorine.
Question
Describe the physical state of the halogen Bromine at room temperature.
Answer
Liquid.
Question
What is the atomicity of Halogens like Chlorine and Iodine?
Answer
Diatomic ($Cl_{2}$, $I_{2}$).
Question
Why do Noble gases have a valency of zero?
Answer
They have a stable, complete electronic configuration (duplet or octet) and do not react.
Question
Term: Electronegativity
Answer
Definition: The tendency of an atom to attract electrons towards itself when combined in a compound.
Question
How does electronegativity change as you move down a group?
Answer
Electronegativity decreases.
Question
In the Modern Periodic Table, where are non-metals generally located?
Answer
In the upper right-hand corner.
Question
What property of an element is the ability to exist in more than one form, such as in Group 14, 15, and 16?
Answer
Allotropy.
Question
Which element in Period 2 is the most electronegative?
Answer
Fluorine ($F$).
Question
Across Period 3, which element is a metalloid?
Answer
Silicon ($Si$).
Question
In Group 17, which element exists as a solid at room temperature?
Answer
Iodine ($I$).
Question
What is the electronic configuration of the noble gas Neon ($Z=10$)?
Answer
$2, 8$.
Question
How does the non-metallic character of elements change across a period from left to right?
Answer
It increases.
Question
What is the valency of an element with atomic number 17?
Answer
One ($1$).
Question
Which group contains elements that are all monoatomic gases?
Answer
Group 18 [Noble gases].
Question
In the Modern Periodic Table, which period is the shortest and consists of only $H$ and $He$?
Answer
Period 1.
Question
What is the chemical nature of the oxides formed by Group 1 metals when reacting with water?
Answer
Strong alkalis.