Question

phet
exercises

1. the periodic table has a great deal of information about every atom. using your periodic table, answer the following questions:

a) what is the atomic number of chlorine (cl)? ____
b) what is the atomic number of tungsten (w)? ____
c) how many protons are there in any cl atom? ____
d) how many protons are there in any te atom? ____
e) can you tell from the periodic table exactly how many neutrons are in an atom? ____

1. complete the following table:

name	symbol	atomic number	mass number	number of neutrons	number of electrons	charge
	³h				1	0
sodium - 22	²²na⁺
		12	24		10
		12	25		12
					13

build an atom

Explanation:

Step1: Recall atomic - number definition

The atomic number is the number of protons in an atom and is found on the periodic table.

Step2: Find chlorine's atomic number

Looking at the periodic table, the atomic number of chlorine (Cl) is 17.

Step3: Find tungsten's atomic number

From the periodic table, the atomic number of tungsten (W) is 74.

Step4: Protons equal atomic number

For any Cl atom, the number of protons is equal to its atomic number, so there are 17 protons.

Step5: Find tellurium's atomic number

The atomic number of tellurium (Te) is 52, so any Te atom has 52 protons.

Step6: Analyze neutron information on periodic table

The periodic table gives the atomic number (number of protons) and the average atomic mass. The number of neutrons can vary (isotopes), so we cannot tell exactly how many neutrons are in an atom from the periodic table alone.

Answer:

a) 17
b) 74
c) 17
d) 52
e) No