Answer:
1. the group number of sodium is 1 and it is a metal
2. the group number of helium is 18 and it is a nonmetal
3. the group number of iodine is 17 and it is a nonmetal
4.the group number of calcium is 2 and it is a metal
5. lithium has similar properties to potassium
6. calcium has similar properties to magnesium
7. neon has similar properties to xenon
8. Iodine has similar properties to chlorine
<span>The characteristics of a wave are given certain names to describe them, and this helps scientists to accurately describe any given wave. The characteristic known as frequency describes the number of waves that pass a point, and it is measured in waves per second, or Hertz, which is given the symbol Hz, but can also be described using the inverse of the SI unit for second, s^-1.</span>
Answer:
Look at the properties of Oxygen and Silicon - the two most abundant elements in the Earth's crust - by clicking on their symbols on the Periodic Table.
Explanation:
Electric motors are an essential part of our daily life as many systems, applications, and services depend on them. Motors today have a long service life and require a minimum level of maintenance to make sure that they perform efficiently. In large buildings, motors have to be maintained on a regular basis because they need to be in operation all the time; one small problem could cause a great loss to the organization.
Usually in large organizations, a motor maintenance program is carried out in which the causes of motor failures are identified and some necessary steps are taken to avoid them or lower their impact. Motors need to be inspected regularly, and other maintenance activities need to be performed to ensure efficient operation. Whenever a problem occurs, it should be corrected immediately to avoid further loss.
A polar molecule is a molecule whose ends have opposite electric charges. An example of a polar molecule is H2O or water. Water has 1 side which is positive and the other side which is negative. It is a dipole which means that the two sides are not having the same charges.
