Chemistry: Periodic Table and Properties

Flashcards covering the history of the periodic table, element classifications, periodic trends such as ionization enthalpy and electronegativity, chemical nomenclature, and general electronic configurations.

What is the Dobereiner Traid rule?

In the group of 3 elements arranged in increasing order of mass, the mass of the 2nd element is the average of the 1st and 3rd element.

How are elements arranged according to Newland's octaves?

Elements are arranged in increasing order of their mass such that every 8th element has similar property as the 1st element.

What is Mendeleev's Periodic Law (P.C.)?

The properties of the element is a periodic function of their atomic mass.

According to the 1984 IUPAC recommendations, how are groups in the periodic table numbered?

The groups are numbered $1-18$, replacing the old numbering scheme of IA-VIIA, VIII, IB-VIIB and 0.

What is the definition of Atomic Radius?

The average distance between the nucleus and the outermost shell.

What is the trend for Atomic Radius (A.R) from Top to Bottom?

A.R generally increases due to the increase in the number of shells (e.g., $Li < Na < K < Rb$).

What is the trend for Atomic Radius from Left to Right and the reason for it?

A.R decreases because the atom decreases due to strong attracts force between proton and $e$.

Compare the size of cations and anions to their parent atoms according to the transcript.

$r_{cat} < r_{atom}$ and $r_{an} > r_{atom}$, meaning anions are larger than cations.

What are Isoelectronic species?

Species which have same number of $e$.

What is Electronegativity (EN)?

The property of an element to attract shared paired of $e$.

What are the trends for Electronegativity (EN)?

L-R: EN increases ($C < N < O < F$); T-B: EN decreases ($F > Cl > Br > I$).

Define the Shredding effect as described in the notes.

The protection of valence $e$ from the attraction ratio uniform for all $e$, applied by inner shells.

What is the trend for Electropositivity (EP) or metallic character?

L-R: EP decreases; T-B: EP increases ($Li < Na < K < Rb < Cs$).

Define Ionization Enthalpy (I.E).

The energy required to remove an $e$ from an isolated gaseous atom.

What is the general trend for Ionization Enthalpy (I.E) across the periodic table?

T-B: decreases ($Li > K > Rb > Cs$); L-R: increases ($Li < Be < B < C < N$).

What is the rule for Successive Ionization Enthalpy (I.E)?

The value of the next I.E is always greater than the previous I.E ($I.E_2 > I.E_1$).

Define Electron Gain Enthalpy (Electron affinity).

The energy required to gain an $e$ by an isolated gaseous atom.

According to the notes, what are the three reasons for the anomalous behaviour of 2nd period elements?

(1) Absence of d-orbitals, (2) High Charge size ratio, and (3) High Polorisation value.

What is Valency?

The combining capacity of an element to complete their octate.

How is Oxidation state defined?

The comparable charge on an atom due to E.N difference, which can be $-$ , $+$ , or $0$.

What are the three oxidation states for oxygen mentioned in the notes?

(i) Oxide ($0^{-2}$), (ii) peroxide ($0_2^{-2}$), and (iii) superoxide ($0_2^{-}$).

What is the general electron configuration for s-block elements?

$$ns^{1-2}$$

What is the general electron configuration for p-block elements?

$$ns^2 np^{1-6}$$

What is the general electron configuration for d-block elements?

$$ns^{1-2} (n-1) d^{0-10}$$

What is the general electron configuration for f-block elements?

$$ns^2 (n-2) f^{0-14} (n-1) d^{0-1}$$

What are the names for the ions $ClO_4$, $ClO_3$, and $ClO_2$?

$ClO_4$: Perchlorate; $ClO_3$: Chlorate; $ClO_2$: Chlorite.

What are the names for the ions $S_2 O_3^{2-}$ and $S_2 O_2^{2-}$?

$S_2 O_3^{2-}$: Thiosulphate; $S_2 O_2^{2-}$: Thessalphite.

What is the formula and name for the ion composed of Nitrogen listed after Nitrite and Nitride?

$N_3^-$: Azide.

What is the formula for Chocomic acid?

$$H_2 Cr_2 O_4$$

What is the name for the acid with the formula $HN_3$?

Hydrazoic acid