Note that your final mark will not be saved in the system.
Model of the atom Typeit
Type the correct answers into the spaces. Fill all the spaces before clicking ‘Check Answers!’
An atom is the smallest part of an that can exist. Atoms contain tiny negative particles called , whose discovery led to the development of the model. This model was later replaced by the model, which suggests that most of the mass of an atom is concentrated at its centre, the . This mass consists of neutral particles called , and positively charged particles called , both of which have a relative mass of 1. Niels adapted the model by including electrons orbiting the central mass at fixed distances called .
The atomic number, i.e. the number of in an atom, is unique for each element. The is the sum of the number of protons and neutrons in an atom. The number of neutrons in an element is not always the same, so there can be several of the same element. Their natural abundance is taken into account when calculating the of an element.
are substances which contain more than one element chemically bonded together and which can only be separated by chemical reactions. In contrast, are combinations of substances which are more loosely bound, and which can be separated physically by processes such as distillation.