Inorganic Chemistry - Classification of Elements and Periodicity in Properties

Practice flashcards covering the history of periodic table development, including various classification rules, drawbacks, and Mendeleev's periodic law.

According to Lavoisier's classification, how are metals and non-metals defined?

Metals have a tendency of losing electrons, while non-metals have a tendency of gaining electrons.

What is the formula for Prout's Hypothesis (Unitary theory) regarding atomic weight?

$\text{Atomic weight of element} = n \times (\text{Atomic weight of one hydrogen atom})$, where $n$ is the number of hydrogen atoms ($1, 2, 3, \dots$).

What were the specific drawbacks of Prout's Hypothesis mentioned in the notes?

Every element cannot be formed by Hydrogen, and the atomic weights of all elements were not found as whole numbers (e.g., $Cl = 35.5$ and $Sr = 87.6$).

What is the core principle of the Dobereiner Triad Rule [1817]?

In groups of three elements with similar chemical properties (Triads), the atomic weight of the middle element is nearly equal to the average atomic weight of the first and third elements.

List the specific examples of Dobereiner Triads provided in the transcript.

$Cl, Br, I$; $Ca, Sr, Ba$; $K, Rb, Cs$; $P, As, Sb$; $S, Se, Te$; $H, F, Cl$; and $Sc, Y, La$.

What is a major limitation of the Dobereiner Triad Rule regarding element classification?

It is not applicable for $d$ and $f$-block elements, and all known elements could not be arranged as triads.

What was the key observation of Newland's Octave Rule [1865]?

The properties of every $8^{th}$ element were similar to the $1^{st}$ element, similar to musical vowel notation.

What are the two major drawbacks of Newland's Octave Rule?

The rule is valid only up to $Ca$ (Calcium), and noble gases were not discovered at that time.

Who created the cylindrical periodic table known as the Telluric Helix in 1862?

Alexandre-Emile Beguyer de Chan Courtois.

What are the characteristics of the Telluric Helix construction?

It is a spiral graph drawn on a vertical cylinder at a $45^{\circ}$ angle to its axis, with the base divided into $16$ equal parts.

In Lothar Meyer's Curve [1869], what element types occupy the top (peak) positions?

Alkali metals.

In Lothar Meyer's Curve, which elements occupy the ascending and descending positions respectively?

Halogens occupy the ascending positions, and alkaline earth elements occupy the descending positions.

What is the fundamental law behind Mendeleev’s Periodic Table [1869]?

The physical and chemical properties of elements are a periodic function of their atomic mass.

How did Mendeleev define the terms 'periods' and 'groups'?

Horizontal rows are called periods and vertical columns are called groups.

What formula did Mendeleev use for the correction of doubtful atomic weights?

$\text{Atomic weight} = \text{Valence} \times \text{Equivalent weight}$.

Which modern elements correspond to Mendeleev's predictions for Eka-Aluminium, Eka-Boron, and Eka-Silicon?

Eka-Aluminium is Gallium ($Ga$), Eka-Boron is Scandium ($Sc$), and Eka-Silicon is Germanium ($Ge$).

Feel Of Concept Is The Real Motivation.