Question

4.3 atomic structure

1. experiments by j.j. thomson showed that atoms have

sketch the cathode ray tube experiment and label its components: (late 1890s)
sketch the pudding model and label its components:

1. rutherfords experiment (1911) discovered the nuclear atom

he used particles and thin gold foil to demonstrate:
atoms have a dense center of positive charge called the
the nucleus, which is at the center of the atom, consists of (positively charged) and (uncharged).
electrons move around the nucleus. sketch rutherfords model:

1. introduction to the modern concept of atomic structure

particle	relative mass	relative charge
proton		+1
	1839	none

1. neils bohr (1913) discovered that electrons in the atom can only occupy certain energy levels around the nucleus. sketch bohrs model:
2. isotopes are atoms with the same number of protons but different numbers of neutrons.

a particular isotope is represented by the symbol (_{z}^{a}x)
where a = number (sum of protons and neutrons)
z = atomic number (number of )
x =

Explanation:

Step1: Recall Rutherford's experiment

Rutherford used alpha ($\alpha$) - particles in his experiment.

Step2: Identify nucleus components

The nucleus consists of protons (positively - charged) and neutrons (uncharged).

Step3: Recall electron charge

Electrons have a relative charge of - 1.

Step4: Recall proton mass

The relative mass of a proton is 1836 (approximate value compared to an electron's relative mass of 1).

Step5: Identify neutral particle

The neutral particle with a relative mass of 1839 is the neutron.

Step6: Recall isotope notation

In the isotope notation $_{Z}^{A}X$, $A$ is the mass number (sum of protons and neutrons), $Z$ is the atomic number (number of protons), and $X$ is the chemical symbol of the element.

Answer:

1. Alpha; proton; neutron
2. - 1; 1836; Neutron
3. Mass; protons; Chemical symbol of the element

(Note: Sketch - related parts cannot be provided in this text - based format. For the cathode - ray tube experiment, it has components like cathode, anode, and the path of the cathode rays. Thomson's plum - pudding model has electrons embedded in a positively - charged sphere. Rutherford's model has a small, dense nucleus with electrons orbiting around it. Bohr's model has electrons in specific energy levels around the nucleus.)