Question

directions: answer the following questions on the lines provided.

1. how is the chemical symbol of an element determined?
2. what are atoms composed of?
3. are electrons, protons, or neutrons the smallest particles? if not, what are?
4. how many types of quarks are there and what is the name of one of them?
5. why do scientists use models to study atoms?
6. why has the atomic model changed over time?
7. why is the current atomic model called the “electron cloud model”?

directions: match the term in column i with the definition in column ii. write the letter of the correct definition in the blank at the left.
column i
____ 8. electron
____ 9. neutron
____ 10. nucleus
____ 11. proton
____ 12. quark
column ii
a. positively - charged particle
b. negatively charged particle
c. neutral particle
d. smaller particles that make up protons and neutrons
e. positively charged center of an atom

Explanation:

Step1: Chemical symbol determination

The chemical symbol of an element is usually the first one - or two - letters of its English or Latin name. For example, hydrogen is 'H' (first - letter), and carbon is 'C'. Some elements with Latin names have symbols based on the Latin name, like iron which has the symbol 'Fe' from 'ferrum' in Latin.

Step2: Atoms composition

Atoms are composed of a nucleus containing protons and neutrons, and an electron - cloud of electrons surrounding the nucleus. Protons are positively charged, neutrons are neutral, and electrons are negatively charged.

Step3: Smallest particles

Electrons, protons, and neutrons are not the smallest particles. Quarks are smaller particles that make up protons and neutrons. There are six types of quarks: up, down, strange, charm, top, and bottom. An example of a quark is the up - quark.

Step4: Quarks types and name

There are six types of quarks: up, down, strange, charm, top, and bottom. One of them is the up - quark.

Step5: Use of models to study atoms

Scientists use models to study atoms because atoms are extremely small and cannot be directly observed. Models help in visualizing and understanding the structure and behavior of atoms, making it easier to explain and predict atomic phenomena.

Step6: Change of atomic model

The atomic model has changed over time because as new experimental evidence and discoveries are made, our understanding of the atom evolves. For example, the discovery of electrons led to the plum - pudding model, and later the discovery of the nucleus led to the Rutherford model.

Step7: Name of current atomic model

The current atomic model is called the 'Electron Cloud Model' because it represents electrons as a cloud of negative charge surrounding the nucleus. The probability of finding an electron in a particular region is represented by the density of the cloud.

Step8 - 12: Matching

1. b. negatively charged particle (electron)
2. c. neutral particle (neutron)
3. d. positively charged center of an atom (nucleus)
4. a. positively charged particle (proton)
5. e. smaller particles that make up protons and neutrons (quark)

Answer:

1. Usually the first one - or two - letters of its English or Latin name.
2. A nucleus containing protons and neutrons, and an electron - cloud of electrons surrounding the nucleus.
3. No, quarks are smaller; up - quark is an example of a quark.
4. Six types: up, down, strange, charm, top, and bottom; up - quark.
5. Because atoms are extremely small and cannot be directly observed; models help in visualization and understanding.
6. Due to new experimental evidence and discoveries that evolve our understanding of the atom.
7. Because it represents electrons as a cloud of negative charge surrounding the nucleus.
8. b
9. c
10. d
11. a
12. e