Question

1. give the symbol and number of electrons in a neutral atom of: uranium, boron, antimony, chlorine, iodine, xenon
2. give the symbol and number of neutrons in one atom of: (to get “mass number”, you must round the “atomic mass” to the nearest whole number) show your calculations. barium, carbon, fluorine, europium, bismuth, hydrogen, magnesium, mercury
3. name the element which has the following numbers of particles: a. 26 electrons, 29 neutrons, 26 protons b. 53 protons, 74 neutrons c. 2 electrons (neutral atoms) d. 20 protons e. 86 electrons, 125 neutrons, 82 protons (charged atom) f. 0 neutrons
4. if you know only the following information can you always determine what the element is? (yes/no). a. number of protons b. number of neutrons c. number of electrons in a neutral atom d. number of electrons

Explanation:

Step1: Recall element - property relationships

The atomic number of an element is equal to the number of protons. In a neutral atom, the number of electrons is equal to the number of protons. The number of neutrons = mass number - atomic number.

For 11a:

The number of protons determines the identity of an element. Each element has a unique atomic number (number of protons). So if we know the number of protons, we can always determine the element.

Answer:

Yes

For 11b:

Different isotopes of the same element can have different numbers of neutrons. So just knowing the number of neutrons is not enough to determine the element.