The concept of resonance is required for certain molecules because the localized electron model assumes electrons are located between a given pair of atoms in a molecule.
Answer:
metallic bond
because this diagram is electron gas theory which shows metallic bond
Answer:
Cell membrane and cytoplasm
Explanation:
Cell membrane is the layer that surronds the cell and it is made up of lipids and proteins. It is made up of a kind of fatty acids based lipids i.e phospholipids and sterols.
Cytoplasm is a thick fluid that is found in the cell membranes. It acts as buffer and protect cells organelles and DNA from damage. It is made up of water, p, lipids, proteins, inorganic salts, nucleic acids.
Döbereiner grouped the known elements into <em>triads</em> (sets of three) so that
• The <em>atomic mass of the middle element</em> was approximately the average of the other two
• The <em>chemical properties of the middle element</em> were between those of the other two
• The <em>physical properties of the middle element</em> were between those of the other two
One example of a triad is Li – Na – K.
(a) Atomic mass of Na = 23.0 u
Average atomic mass of Li and K = (6.9 u + 39.1 u)/2 = 46.0 u/2 = 23.0 u
(b) Li reacts slowly with water. Na reacts rapidly. Potassium reacts violently.
(c) Melting point of Na = 371 °C.
Average melting point of Li and K = (454 °C + 330 °C)/2 = 784 °C/2
= 392 °C
