Answer is: the discovery of sub atomic particles like electrons.
J. J. Thomson discovered the electron in 1897.
His "plum pudding" model (1904) suggested: the electrons are embedded in the positive charge.
With this model, he abandoned his earlier hypothesis (the atom was composed of immaterial vortices).
J.J. Thomson placed two oppositely charged electric plates around the cathode ray. He did experiments using different metals as electrode materials and found that the properties of the cathode ray remained constant no matter what cathode material he used.
Tomson concluded that atoms are divisible and that the corpuscles are their building blocks (atoms are made up of smaller particles).
1a. calcium chloride (CaCl2)
b. 2HCl (aq) + Ca(OH)2 (s) —> CaCl2 (aq) + 2H2O (l)
i’m not sure about the rest but i hope this helped ^^
Answer:
B
Explanation:
B, H2O + Na The elements toward the bottom left corner of the periodic table are the metals that are the most active in the sense of being the most reactive. Lithium, sodium, and potassium all react with water,
Answer:
F. 2NO + 02 —> 2NO
H. 4NH3 + 502 —> 4NO + 6H20
Explanation:
The law of conservation of mass states that matter can neither be created nor destroyed during a chemical reaction but can be convert from one form to another.
2NO + 02 —> 2NO
From the above, the total number of N on the left balance the total number on the right i.e 2 atoms of N on both side of the equation.
The total number of O on the left balance the total number on the right i.e 2 atoms of O on both side of the equation. This is certified by the law of conservation of mass.
4NH3 + 502 —> 4NO + 6H20
From the above, the total number of N on the left balance the total number on the right i.e 4 atoms of N on both side of the equation.
The total number of O on the left balance the total number on the right i.e 10 atoms of O on both side of the equation.
The total number of H on the left balance the total number on the right i.e 12 atoms of O on both side of the equation.
This is certified by the law of conservation of mass.
The rest equation did not conform to the law of conservation of mass as the atoms on the left side did not balance those on the right side
Answer: This is a list of the seven diatomic elements. The seven diatomic elements are:
Hydrogen (H2)
Nitrogen (N2)
Oxygen (O2)
Fluorine (F2)
Chlorine (Cl2)
Iodine (I2)
Bromine (Br2)
All of these elements are nonmetals, since the halogens are a special type of nonmetallic element. Bromine is a liquid at room temperature, while the other elements all gases under ordinary conditions. As the temperature is lowered or pressure is increased, the other elements become diatomic liquids.
Astatine (atomic number 85, symbol At) and tennessine (atomic number 117, symbol Ts) are also in the halogen group and may form diatomic molecules. However, some scientists predict tennessine may behave more like a noble gas.
While only these seven elements routinely form diatomic molecules, other elements can form them. However, diatomic molecules formed by other elements are not very stable, so their bonds are easily broken.
How to Remember the Diatomic Elements
The elements ending with "-gen" including halogens form diatomic molecules. An easy-to-remember mnemonic for the diatomic elements is: Have No Fear Of Ice Cold Beer
Explanation:
SORRY if you don't understand!
