SUMMATIVE NO. 4 IN SCIENCE 8 (Quarter 2)

Which statement about elements is true?

• All atoms of an element have different numbers of protons

• All atoms of an element have the same number of protons

• Elements can be broken down by physical means

• Elements are made up of two or more kinds of atoms

What does the atomic number of an element represent?

• The total number of particles in an atom

• The number of electrons plus neutrons

• The number of protons in the nucleus

• The number of isotopes of the element

Which of the following statements best describes a compound?

• It is made up of atoms of the same element only.

• It has a fixed ratio of elements chemically combined.

• It can be separated by filtration or evaporation.

• It is a mixture of metals.

Which of the following pairs are both examples of pure substances?

• Air and saltwater

• Iron and water

• Milk and sugar solution

• Soil and sand

What happens when elements chemically combine?

• They form mixtures

• They form compounds with new properties

• They separate easily

• Their properties remain the same

Which of the following is a compound?

• Silver

• Carbon dioxide

• Oxygen

• Nitrogen

The Law of Octaves was proposed by:

• John Newlands

• Dmitri Mendeleev

• Lothar Meyer

• Johann Döbereiner

Who is known as the “Father of the Periodic Table”?

• Moseley

• Newlands

• Mendeleev

• Döbereiner

What did Henry Moseley use to arrange the elements in the modern periodic table?

• Atomic mass

• Valence electrons

• Atomic number

• Density

Johann Döbereiner’s triads were based on:

• Increasing atomic number

• Increasing atomic mass

• Similar physical and chemical properties

• Alphabetical order of elements