Mass number and atomic number are two important pieces of information about a nucleus.

You are watching: An atom has 17 protons and 18 neutrons

A nucleus can be represented using the symbol notation:

<_Z^A extrmX>

Where:

A is the mass numberZ is the atomic numberX is the chemical symbol of the elementA - Z = number of neutrons N

For example, chlorine (Cl) can be shown as:

*
Carbon has three isotopes: (_6^12 extrmC), (_6^13 extrmC) and (_6^14 extrmC). They all barisalcity.orgntain six protons, but six, seven and eight neutrons respectively.

(_7^14 extrmN) and (_6^14 extrmC) are not isotopes.

They have the same mass number, A, but different atomic number, Z, and different chemical symbol - they are not the same element.

If the number of protons changes, then it is a different element.

Question

How many protons does (_6^14 extrmC) barisalcity.orgntain?

Reveal answer
up


down
The atomic number is 6 so (_6^14 extrmC) barisalcity.orgntains six protons.

Question

How many neutrons does (_6^14 extrmC) barisalcity.orgntain?

Reveal answer
up


down
Number of neutrons = mass number - atomic number = 14 - 6 = 8 neutrons.

Question

Write down the number of particles in the following nuclei:

<_30^64 extrmZn>

<_92^238 extrmU>

<_1^3 extrmH>

Reveal answer
up


down
<_30^64 extrmZn>

Number of protons Z = 30Number of protons + neutrons A = 64Number of neutrons N = 64 - 30 = 34Since this is a nucleus there are no electrons

There are 30 protons and 34 neutrons.

<_92^238 extrmU>

Number of protons Z = 92Number of protons + neutrons A = 238Number of neutrons N = 238 - 92 = 146Since this is a nucleus there are no electrons

There are 92 protons and 146 neutrons.

See more: How Much Oil Does A Lmm Duramax Hold, Duramax Fluid Capacities

<_1^3 extrmH>

Number of protons Z = 1Number of protons + neutrons A = 3Number of neutrons N = 3 - 1 = 2Since this is a nucleus there are no electrons

There is 1 proton and 2 neutrons.


2Page 2 that 4
Glossary
up


down

More Guides

The structure of the nucleus - CCEA

Struggling to get your head round revision or exams?

Our tips from experts and exam survivors will help you through.

Get advice here

Links


GCSE SubjectsGCSE Subjects
up
down

Explore the barisalcity.org