C1.7 - R* Ions, atoms and isotopes

Question 1

If an atom gains 1 or more electrons, why does it gain an overall negative charge?

Answer 1

If an atom gains:
1. 1
Or,
2. More
electrons, it gains an overall negative charge, because it has more electrons than protons

Question 2

Ion

Answer 2

An ion is a:
1. Charged atom
Or,
2. Group of atoms
produced by the loss or gain of electrons

Question 3

How big is an atom?

Answer 3

An atom is about 1/10th of a billionth of a metre across

Question 4

Atoms of the same element always have the same number of protons, but what can they have different numbers of?

Answer 4

Atoms of the same element always have the same number of protons, but they can have different numbers of neutrons

Question 5

Isotopes

Answer 5

Isotopes are different forms of the same element, which have the same number of protons, but a different number of neutrons

Question 6

What do isotopes have?

Answer 6

Isotopes have:

1. The same atomic number
2. Different mass numbers

Question 7

Why is the nucleus sometimes radioactive?

Answer 7

The nucleus is sometimes radioactive, because sometimes extra neutrons make the nucleus unstable

Question 8

Why aren’t all isotopes radioactive?

Answer 8

All isotopes aren’t radioactive, because they are simply atoms of the same element that have different masses

Question 9

What do samples of different isotopes of an element have in relation to physical properties?

Answer 9

Samples of different isotopes of an element have different physical properties

Question 10

What do samples of different isotopes of an element have in relation to chemical properties?

Answer 10

Samples of different isotopes of an element always have the same chemical properties

Question 11

Why is the electronic structure the same for all isotopes of an element?

Answer 11

The electronic structure is the same for all isotopes of an element, because their atoms will have the same number of:

1. Protons
2. Therefore electrons

Question 12

The 1st isotope of hydrogen

Answer 12

The 1st isotope of hydrogen is Hydrogen (hydrogen-1)

Question 13

The 2nd isotope of hydrogen

Answer 13

The 2nd isotope of hydrogen is Deuterium (hydrogen-2)

Question 14

The 3rd isotope of hydrogen

Answer 14

The 3rd isotope of hydrogen is Tritium (hydrogen-3)

Question 15

The 3 isotopes of hydrogen are:
Hydrogen (hydrogen-1)
Deuterium (hydrogen-2)
Tritium (hydrogen-3).
They all have a different mass and tritium is radioactive, but what is the same about them?

Answer 15

The 3 isotopes of hydrogen all have a different mass and tritium is radioactive, but they all have identical chemical properties

Question 16

Relative atomic mass

Answer 16

Relative atomic mass is an average mass taking into account the different:
1. Masses
2. Abundances (amounts)
of all the isotopes that make up the element

Question 17

The formula for relative atomic mass (Ar)

Answer 17

The formula for relative atomic mass (Ar) is:

Relative atomic mass (Ar) = Sum of (isotope abundance x isotope mass number) ÷ Sum of abundances of all the isotopes

Question 18

A very popular example of a pair of isotopes

Answer 18

A very popular example of a pair of isotopes are:

1. Carbon-12
2. Carbon-13

Question 19

Number of PEN in carbon-12

Answer 19

The number of PEN in Carbon-12 are:

1. 6 protons
2. 6 electrons
3. 6 neutrons

Question 20

Number of PEN in carbon-13

Answer 20

The number of PEN in Carbon-13 are:

1. 6 protons
2. 6 electrons
3. 7 neutrons

Question 21

Why is relative atomic mass (Ar) used, instead of mass number when referring to the element as a whole?

Answer 21

Relative atomic mass (Ar) is used, instead of mass number when referring to the element as a whole, because many elements can exist as a number of different isotopes

Question 22

If an atom gains 1 or more electrons, it gains an overall negative charge, because it has more electrons than protons.
The atom has become a what?

Answer 22

The atom has become a negative ion

Question 23

Samples of different isotopes of an element have different physical properties.
Example

Answer 23

For example, they will have a different density and they:
1. May
Or,
2. May not be
radioactive

Question 24

Samples of different isotopes of an element always have the same chemical properties, because what?

Answer 24

Samples of different isotopes of an element always have the same chemical properties, because their reactions depend on their electronic structures

Question 25

The 3 isotopes of hydrogen all have a different mass and tritium is radioactive, but they all have identical chemical properties.
Example

Answer 25

For example, the 3 isotopes of hydrogen all react with oxygen to make water