Periodic Table Flashcards
What is the Modern periodic law?
The periodic law states that the physical and chemical properties of elements are a periodic function of their atomic numbers.
What determines the position of an element in the periodic table?
The position of an element is determined by its atomic number and its electron configuration.
Which element is the most abundant in the Earth’s crust?
Oxygen is the most abundant element in the Earth’s crust.
What is the general trend in atomic radius as you move from left to right across a period?
The atomic radius generally decreases as you move from left to right across a period.
How does the reactivity of alkali metals change as you move down the group?
The reactivity of alkali metals increases as you move down the group.
What is atomic radius?
The distance from the center of nucleus of an atom to outermost shell of electrons.
What is covalent radius?
Half of the internuclear distance (bond length) between two like atoms bonded by single covalent bond.
Single Covalent Bond & Like atoms
What is Van der Waal’s radius?
Half of the distance between nuclei of two non bonded neighboring atoms held by van der Waals force of attraction.
Non Bonded & Adjacent Molecules
Which radius Van der Waal’s radius or covalent radius greater?
Van der Waal’s radius
What is metallic radius?
It is defined as the half of the distance between nuclei of two adjacent atoms in close-packed crystal lattice.
Which has a larger radius? H or He
He
Van der Waal’s radius > Covalent radius
Which group element has the biggest radius along a period?
Noble elements (Group 18)
Order of ionic radius of atom, cation and anion
Anion > Atom > Cation
(Shielding effect: Anion>Cation)
Anion : E Nuclear Charge decreases
Cation : E Nuclear Charge increases
What is ionic radius?
The distance between the center of the nucleus and a point up to which the nucleus has its influence in an ion is ionic radius.
What is the formula for Iso-electronic species?
Size is inversely proportional to atomic number
Size ∝ 1/Z
Why is cation smaller in size than its parent atom?
When an electron is lost, electron-electron repulsion (and therefore, shielding) decreases and the protons are better able to pull the remaining electrons towards the nucleus and effective nuclear charge increases. Also when it loses a shell.
Anion is larger in size than parent atom. Why? Explain
An additional electron occupies an outer orbital, there is increased electron-electron repulsion (and hence, increased shielding) which pushes the electrons further apart.
The electrons now outnumber the protons in the ion, the protons can not pull the extra electrons as tightly toward the nucleus; this results in decreased effective nuclear charge.
Why do atomic radii decreases across the period? Explain
The atomic radius decreases because the effective nuclear charge increases as the number of protons in the nucleus increases along a period. The shielding effect remains relatively constant since the additional electrons are added to the same energy level. As a result, the valence electrons are pulled closer to the nucleus, leading to a smaller atomic radius.
Why do atomic radii increase down the group in periodic table?
Addition of Electron Shells, Increased Shielding, Reduced Effective Nuclear Charge
What are acid and basic radicals?
Acid radicals are derived from acids and carry a negative charge, while basic radicals are derived from bases and carry a positive charge.
Dobereiner’s Triad
- Elements having similar properties can be arranged in group of 3 called triad
-Lithium, Sodium Potassium
-Chlorine, Bromine and Iodine - Atomic mass of Na = (Li + K) / 2
Newland’s law of octaves
-Repetition of similar character when arranged in increasing order of atomic weights.
Lother Mayer’s atomic volume curve
- X axis : Atomic weight
- Y axis : Atomic Volume
- Elements having similar properties occupy similar positions in the curve.
How many groups and periods were there in Mendeleev’s periodic table?
Group - 9
Period - 7
