Which of the following particles are used in determining the position of an element within the periodic table?

• protons only

• neutrons only

• electrons only

• protons and electrons

The isotope 50-Vanadium has a mass number of 50. How many neutrons are present in this isotope?

• 23

• 27

• 50

• 73

The atomic number of an element represents:

• 1. the number of electrons.

• 1. the number of protons.

• 1. the number of neutrons.

• 1. the number of protons added to number of electrons.

1. The nucleus of an atom consists of:

• 1. electrons and protons.

• 1. electrons and neutrons.

• 1. protons only.

• 1. protons and neutrons.

1. How many protons does a sodium atom have?

• 10
• 11
• 5
• 12

1. The atomic number of phosphorus is:

• 1. 15

• 1. 16

• 1. 31

• 1. 30

1. The charge of an electron is:

• 1. Negative.

• 1. Neutral.

• 1. Positive.

• 1. Nothing.

1. Which of the following are atoms of the same element?

• 1. U and Y

• 1. U and X

• 1. X and Y

• 1. U and V

Which of the following would not increase the rate of a chemical reaction?

• decrease in temperature

• increase in concentration of reactants
• increase in pressure
• presence of a catalyst

What is the formula for dibromine tetriodide?

• Br2I4
• BrI2
• BrI4
• Br2I2