Who first proposes the ideas that all matters are made of atoms?
Democritus.
100
What is the shape that the metalloids form on the Periodic Table?
A staircase-shape.
100
How to find out the mass number of an element?
Find out the total number of protons and neutrons in the nucleus of an atom.
100
What are ionic compounds?
Compounds that are formed with metals and non-metals
100
What are the five modern famous scientist that contributed in the atomic theory that are mentioned in the textbook?
John Dalton, Michael Faraday, J.J. Thomson, Ernest Rutherford, Niels Bohr
200
What does Dalton use as a model for his theory?
A billiard ball or a sphere.
200
What can be found in the sample entry from the Periodic Table of an element? (List three things)
Answers may be vary:
Ex: Atomic number, density at SATP, most common ion charge, symbol of element, name of element, and atomic mass.
200
Why are different elements emit different colours?
Because each element has a unique separation of its allowed electron shells.
200
Which group in the periodic table contains the least reactive metal? what is the group name?
Group 18, noble gases
200
Draw a Bohr diagram for sulfur ion.
...
300
What forms a molecule? (Be Specific).
Two or more non-metallic atoms.
300
What is the average of the mass numbers of all the naturally occurring isotopes?
The atomic mass.
300
An atom belongs to first 20 elements category. It has 13 electrons. How many shells are there? And how many electrons are there in each shell?
There are three shells and 2 electrons in the first shell, 8 in the second shell, and 3 in the third shell.
300
Which of the two group in the periodic table contains the most reactive elements?
Group 1 and Group 17
300
An unknown element X have 20 protons
1) What is the real element name?
2) How many neutrons does this element have?
3) How many shell does it have?
1) Calcium
2) 20
3) 4
400
Give three statements from Michael Faraday's revisioned theory of atoms.
-Matter must contain positive and negative charges.
-Opposite charges attract, and like charges repel.
Atoms combine to form the particles of a compound because of the electrical attraction between charged atoms.
-Atoms combine to form the particles of a compound because of the electrical attraction between charged atoms.
400
What does not change when the atom forms an ion?
The number of protons.
400
Water has two parts of hydrogen and one part of oxygen, why?
Because hydrogen has a charge of 1+ and oxygen has a charge of 2-, so if the compound want to be neutral, there must be 2 hydrogen and 1 oxygen.
400
why are the elements in group 1 and group 17 so reactive?
Group 1: They have one electron on their outer shell, that make them easily to lose electron
Group 7: They have one vacant "spot" on their outer shell, that make them easily to gain electron
400
If the size of a hydrogen atom is the size of the apple, then the real apple will be as large as ...
Earth!
500
Describe three things about electrons by using Rutherford's theory?
Answer may be vary:
-The electrons orbit the nucleus.
-The mass of an electron is 1/1800 the mass of a proton.
-The size of the atom is determined by the size of the orbit of the electrons.
-There is only empty space between the electrons and the nucleus.
500
List three ways how to classify the elements in the Periodic Table?
-By separating them by their physical properties into metals, metalloids, and non-metals.
-By family, which is based on common physical and chemical properties.
-By groups (or columns).
500
What group is Sodium in? What are the properties of this group? What is another example for this group?
group 1, they are highly reactive elements tend to lost one electron. another example can be potassium
500
What are covalent bonds? and what is the difference between covalent bonds and ionic bonds?
Covalent bond: bonds created during the process of sharing electrons
Difference between those two: Ionic bonds formed when electron are transferred, which can only happen with Ionic compounds, but covalent bonds can exist in a molecular compound
500
you have discovered a new substance that might be a element. What questions can you ask about yourself to identify whether if the substance is a element or not? Write 3 questions
Answer may vary.
Can it be broken down to something simpler?
Can it be created with other substances?
Does their colour spectrum conflict with the known spectrum?
etc.