Table 1 shows the proton number, nucleon number and number of electrons for four particles. Which pair of particles are isotopes of the same element?

• G and L
• J and L
• L and M
• J and M

Which isotope is used by doctors to detect and treat thyroid disease?

• C-14
• Co-60
• I-131
• U-238

Which pairing of isotopes and their use is correct?

• Iodine-131; to make atomic battery
• Carbon-14; to measure the density of concrete
• Cobalt-60; to treat cancer
• Uranium-238; dating of organic artifacts

What is the use of isotopes cobalt-60 and iodine-131

• Dating of geological formations
• Measuring and detection in industries
• Medical procedures
• Generating nuclear energy

Isotopes are atoms of the same element with the same number of protons but different number of neutrons

State one use for the isotopes Sodium-24.

• Detecting leakage

• Detecting leakage in underground pipes

Magnesium exists naturally as three isotopes, which are 79% of Magenesium-24, 10% of Magnesium-25 and 11% of Magnesium-26. Calculate the relative atomic mass of magnesium.

• 24.32

Figure 1 shows a graph of temperature against time for vapour X as it is cooled until it becomes a solid. Name the process of change in state of matter when vapour X is cooled.

• sublimation

Determine the number of valence electrons for the atoms in Figure 2.18

• P;7 , Q;16 , R;12 , S;26
• P;5 , Q;6 , R;2 , S;8

A chlorine atom has 17 protons and 18 neutrons. What is the proton number and nucleon number of the chlorine atom?

• Proton 17 nucleon 35

• protons 17 nucleon 35

• proton number 17 nucleon number 35

Unsur X has a boiling point of -34 degree celcius. What is the physical state of element X at a room temperature?

• Solid
• Gas
• Liquid

The following are four steps in scientific investigation. Which sequence is correct

• Q,R,P,S
• R,P,Q,S
• S,Q,P,R
• R,Q,S,P

If your friend's eye comes in contact with a chemical, what is the first action that you must do?

• Report the matter to the teacher
• Wash off the chemical spill
• Bring the friend to the eye wash station to wash his eye
• Ask the friends to sit down and comfort him

Iron atom has proton number 26 and nucleon number 56. Iron atom loses 3 electrons to form an ion. What is the number of each subatomic particle in the iron ion?

• Proton 26, Neutrons 30, Electron 23

• 26,30,23

In the experiment of cooling naphthalene. Why the naphthalene need to be stirred continuosly?

• Avoid supercooling

• Supercooling