<h3><u>Answer</u>;</h3>
= 0.6
<h3><u>Explanation</u>;</h3>
Using Pythagoras theorrem
Base² + height ² = Hypotenuse²
Thus;
Base² = 15² - 12²
= 81
Base = √81 = 9
But; cosine = adjacent/hypotenuse
Hence; cos θ = 9/15
<u>= 0.6 </u>
Answer:
b. negative
Explanation:
neutrons have a negative charge and protons have a proton has a positive charge
The answers are as follows:
1. B.
A typical atom is made up of three different particles, which are electron, proton and neutron. The proton and the neutron are located inside the nucleus of the atom while the electron orbit round the nucleus.
2. C
The number of proton in an atom determines the atomic number of that atom. Atom are positively charged particles and they do no participate in chemical reactions. The number of proton of an element remain constant at all time while the number of neutrons and the electrons in the atom may change.
3. B.
The first periodic table was created by Dmitri. He arranged the periodic table in such a way that, elements with similar properties fall into the same column in his periodic table. This was because, he arranged the periodic table on the basis of their physical and chemical properties.
4. A
The elements in the periodic table are arranged in horizontal row and vertical column. The column on the periodic table divides the elements into groups.
A row of element on the periodic table is called PERIOD. For elements on the same period, they have the same number of atomic orbitals.
5. A
Chemical symbol refers to the one or two letters which are used to represent a particular element. Chemical symbols are derived in a variety of ways. The chemical symbols make it possible for one to recognize an element quickly and to write it in an abbreviated form when writing chemical equations.
6. A.
An object is said to be ductile if it can be pulled into a long wire. It refers to an element's capacity to be pulled into a thin wire without the element been deformed. This is one of the properties of metals. Ductability makes it easier for one to work with a metal.
7. C
When metals atoms react with other atoms, the metal atoms lose electrons, this is because, metals usually have a low number of electrons in their outermost shells, which they always preferred to donate in order to achieve octet form.
8. B
Particle accelerator is a machine that accelerate elementary particles to very high energies, thus producing beam of charged particles which can be used for a lot of different purposes.
It is the mathematical and conceptual framework for contemporary Elementary practical physicas. if that make sense to you.
