Research suggests that crochet probably developed most directly from Chinese needlework, a very ancient form of embroidery known in Turkey, India, Persia and North Africa, which reached Europe in the 1700s and was referred to as tambouring, from the French tambour or drum.
POLAR BONDS. 1) Covalent bond between two atoms with unequal electronegativities results in unequal sharing of electrons. 2) Unequal electron sharing leads to partially positive and partially negative charges on opposite ends of the bond.When the two atoms involved in a covalent bond both have equal affinity for electrons, the electrons in the bond are evenly shared between them.hese types of covalent bonds are called polar bonds because the electron distribution or charge is unevenly distributed or polarized. Partial charges are represented by lower case delta (+) Î´+ or lower case delta (-) Î´-. A separation of partial charges within a polar covalent bond is referred to as a dipole.
Unequal Sharing of Electrons Produces Polar Bonds. Most chemical bonds are covalent in that electrons are shared, but this sharing need not be equal. The sharing is exactly equal only if the two atoms are identical, as they are in the diatomic elements such as oxygen, O 2. When the two atoms are not identical and the sharing is noticeably unequal, the covalent bond is said to have ionic character or to be polar.