Periodic Table - Consumer Chemistry PDF

PERIODIC TABLE - October 16, 2024 MEANING OF PERIODIC TABLE - Tabular arrangement of chemical elements, organized by atomic mass and electronic configuration HISTORY OF THE PERIODIC TABLE DOBEREINER’s TRIADS (Law of Triads) - Johann Wolfgang Döbereiner - Found two more groups of...

PERIODIC TABLE - October 16, 2024 MEANING OF PERIODIC TABLE - Tabular arrangement of chemical elements, organized by atomic mass and electronic configuration HISTORY OF THE PERIODIC TABLE DOBEREINER’s TRIADS (Law of Triads) - Johann Wolfgang Döbereiner - Found two more groups of similar elements; first was calcium, strontium, and barium; Second was sulfur, selenium, and tellurium. He called these groups of elements triads or Döbereiner's triads. - The physical and chemical properties of the middle element are the average of the other two elements in the triad. JOHN NEWLANDS’ LAW OF OCTAVES (Newland's Law of Octaves) - Arranged elements in octaves, where every eighth element had similar properties. - This arrangement was only true for lighter elements in two rows. DMITRI MENDELEEV (Mendeleev’s Periodic Table) - Occasionally put heavier elements before lighter ones. He arranged elements by increasing atomic weight and grouped them by similar  properties but occasionally placed heavier elements before lighter ones to keep elements with similar properties in the same group (column). - Predicted the existence and properties of undiscovered elements like Gallium and Germanium. He purposely left gaps in his periodic table for elements not yet discovered. And if you have seen his periodic table, it is almost identical to the periodic table that we have today. - Lothar Meyer also had the same idea but Dmitri published his first so he is more widely known but Meyer still contributed to the history of the periodic table. HENRY MOSELEY - Proposed elements should be arranged by Atomic Number, not atomic weight. MODERN PERIODIC LAW - The chemical and physical properties of the element tend to vary periodically in order of increasing atomic number FEATURES OF PERIODIC TABLE PERIODS - Horizontal Rows - Classified based on the number of electron shells. - There are 7 periods GROUPS/FAMILIES - Vertical Rows; Family or Group A and B GROUP A - Representative Elements Types of Elements and Their Oxidation State: Family IA: Alkali metals Family IIA: Alkaline earth metals Family IIIA: Boron family Family IVA: Carbon family Family VA: Nitrogen family Family VIA: Oxygen family Family VIIA: Halogens Family VIIIA: Noble gases GROUP B - Transition Metals Transition Elements: Found in the sub-group. Inner transition elements are radioactive and have unique electron configurations. ELECTRON CONFIGURATION - Arrangement or Distribution of electrons in the orbitals of an atom. - The most stable arrangements are ground states.  - The most unstable arrangements are excited states. PARTS OF THE ELECTRON CONFIGURATION - Energy Level (n) which is any number and it is the distance from the nucleus. The farther from the nucleus, the stronger its energy. Represented by numbers (1, 2, 3, etc.). - Sub level or orbital is either s, p, d, or f - Number of electrons which is the superscript number next to the sub level. Sublevels: SPDF s: Sharp - starts at level 1 ; max 2 p: Principal - starts at level 2 ; max 6 d: Diffuse - starts at level 3 ; max 10 f: Fundamental - starts at level 4 ; max 14 *Special Note: The energy level is like a university, and sublevels are like cars in the parking lot. The SPDF sublevels increase in complexity and energy as you move forward.* WRITING ELECTRON CONFIGURATION Aufbau Principle (Building App Principle) - Electrons enter orbitals of lower energy level first. Pauli’s Exclusion Principle - Maximum of two electrons may occupy a single orbital, but only if the electrons have opposite spins. Hund’s Rule - When electrons occupy orbitals with equal energy, electrons will fill the orbitals sing. Electrons will fill orbitals singly with parallel spins before pairing up in any orbital. *The ion is more stable than the neutral atom because it achieves the noble gas configuration.* Increasing Energy from 1s Orbital: - Start at the beginning of each arrow and follow through all sublevels, filling as you go. Example: 1s → 2s → 2p → 3s → 3p → 4s → 3d → 4p → 5s → 4d → 5p, etc. Example Electron Configurations: 11Na (Sodium) = : complete electron configuration 11Na (Sodium) = : complete noble gas configuration 8 = This ion is isoelectronic (same electron configuration) with the noble gas Neon. The ion is more stable than the neutral atom because it achieves the noble gas configuration. 10Ne = Neon is a noble gas, so its electron configuration is already in the most stable form. Finding the Electron Configuration: - FORMAT – (Energy Level)(S, P, D, F)(Amount of Electrons) If you are given the period, whichever period it is, that’s the energy level of your valence electron which you can use to find the atomic number including the electron configuration of an element. This must also include its group, where if it is in A, the amount of electrons is based on the group number in A. For example, if your element is in 1A, the valence number has 1 electron. But if it is in B, then you remove 2 from the group number. Example, if your element is in 5B, then the amount of electrons in the valence number is 3. Some exceptions exist, such as 8B, which has electrons of 6, 7, and 8. If 1B and 2B are given on the other hand, it will show that it has 9 electrons and 10 electrons. This is because if you DID get the electron configuration instead of the period and group number, you would add 2 instead of removing 2 from the group number. 9 + 2 = 11 and since there are only a maximum of 10 groups, it would go back to 1 leading to 9 electrons being in 1B.