class 9

The chemical symbol for potassium is

• (a) Po

• (b) K

• (c) Ka

• (d) P

According to whom each element had a characteristic atomic mass

• Proust

• Lavoisier

• Dalton

• Newton

What is IUPAC

• International Union of Professional And Creative scientists

• International Union of Pure and Associated Chemistry

• International Union of Pure and Applied Chemistry

• None of these

How were relative atomic masses determined

• Law of constant proportions and compounds formed

• Law of conservation of mass and compounds formed

• Laws of chemical combinations and compounds formed

• Dalton's atomic theory

What is u

• Uniform mass

• Used mass

• Unified mass

• Unused mass

Why was old atomic mass unit of the oxygen element considered relevant

• It reacted with a large number of elements and formed compounds

• It gave masses of most of the elements in rational numbers

• It gave masses of most of the elements in whole numbers

• Because it was artificially made

Which element was chosen as the standard reference for measuring atomic masses

• Carbon

• Oxygen

• Carbon-12 isotope

• None of these

Atomic Mass of calcium

• 38

• 27

• 32

• 40

.

write the formula of the compound formed between elements below:

Be F

answer choices

• BeF2

• Be2F

• BeF

• F2Be

write the formula of the compound formed between elements below:

Ca NO3

• Ca(NO3)2

• Ca(NO3)

• CaNO3 2

• CaNO3