Which of the following is known as ammonia?
NH3
Ammonia is NH₃, with one nitrogen atom and three hydrogen atoms. PH₃ is phosphine and NO₂ is nitrogen dioxide. A nitrate ion requires the negative charge, NO₃⁻; neutral NO₃ should not be labelled nitrate ion.
Which of the following is one of the metals used in LED semiconductor technology?
Lanthanides are often called:
Identify the last element from the fifth period.
Which of the following minerals produces green colour in fireworks?
Dry ice, ammonium chloride, naphthalene balls, and camphor, all these compounds are an example of:
Identify the element that does NOT belong to Period 6 of the Modern Periodic Table.
Which of the following chemicals is used as a preservative to slow browning and discolouration in foods and beverages during preparation, storage and distribution?
Baking soda is ________.
In which year did AEB de Chancourtois organize the elements by atomic weight, by graphing the elements around a cylinder with a circumference of 16 units, corresponding to the weight of oxygen (O)?
The chemical formula of borax is .
Whose Periodic Law was modified and adopted the Atomic number as the basis of Modern Periodic Table?