The Macromolecular Compounds

Macromolecular Compounds The macromolecular compounds have giant, covalent molecules with extremely large molecular lattices. They have very high melting and boiling points. They don’t conduct electricity — not even when molten (except for graphite). They’re usually insoluble in water. Examples of such macromolecules are diamond, silica and graphite. Diamond and Silica(Sand) (3 dimensional structure macromolecular … Read more

Physical Properties of Covalent Compounds

Covalent Compounds Simple MoleculeCovalent compounds can be divided into 2 types: Simple molecular compound Macromolecular compound Simple Molecules Most covalent compounds are made up of independent molecular units, as shown in figure above. The attraction force between molecules is the weak Van der Waals’ force. Properties of Simple Covalent Molecular Substances – Small Molecules! The … Read more

Physical Properties – Ionic Compounds

Ionic Compounds Structure Ionic Compound In an ionic compound, the alternate positive and negative ions in an ionic solid are arranged in an orderly way as shown in the image to the right. The ions can form a giant ionic lattice structure with ionic bond between the ions. The ionic bond is the strong electrical attraction … Read more

Predicting the Molecular Formula of Covalent Compounds

Predicting the Molecular Formula of Covalent Compounds Like the formula of ionic compounds, the formula of most covalent compounds can be predicted by referring to the group in periodic table of the elements in the compound. We can predict the formula of a covalent compound by referring to the valency of the elements in the … Read more

Covalent Compounds – Number of Bonds

Number of Bond There are 3 types of covalent bond: Single covalent bond – sharing of one pair of electrons Double covalent bond – sharing of two pairs of electrons Triple covalent bond – sharing of three pairs of electrons Example Number of electrons Example and type of covalent bond 1 pair type of covalent … Read more

Covalent Bonding

Covalent Bonding Covalent bonds are formed by atoms sharing electrons to form molecules. This type of bond usually formed between two non-metallic elements. In the formation of covalent bonds, atoms of non-metals will combine with each other to donate one, two or three electrons for sharing. The compound formed through the formation of covalent bonds … Read more

Predicting the Formula of Ionic Compound

Predicting the Formula of Ionic Compound We can predict the charge of the ions formed from an element base on the group of the element. From the charge, we can then write the formula of the ionic compound formed. In short, we can predict the formula of an ionic compound if we know the group … Read more

Ionic Bonding

Ionic Bonding Ionic bonds are formed by one atom transferring electrons to another atom to form ions.  Ions are atoms, or groups of atoms, which have lost or gained electrons. The atom losing electrons forms a positive ion (a cation) and is usually a metal. The atom gaining electrons forms a negative ion (an anion) … Read more

Formation of Negative Ions

Formation of Negative Ion Negative ions are formed among atoms of non-metal elements except group-18 elements. Non-metal elements usually located in group 15, 16 and 17 in the periodic table and have 5, 6 or 7 valence electrons. To achieve octet arrangement of electrons, their atoms will receive 3, 2 or 1 electron. As a … Read more

Formation of Positive Ions

Formation of Positive Ion Usually, the atom of metals consists of 1, 2 or 3 valence electrons. In order to achieve octet electrons arrangement, the atoms will release the valence electrons. After releasing the valence electrons, the protons in the nucleus will outnumber the electrons. As a result, positive ions formed. Example: Formation of Ion … Read more