What's the problem ? Hardness is not the definition of a metal.
You need to expand your thinking. EVERY element is solid, liquid, and gas, over different ranges of temperature ... including all of the metals. There are only TWO elements that are liquid AT ROOM TEMPERATURE, and mercury is one of them. But on a mild day at the south pole, mercury is solid too.
A.
Elements in the same group have similar properties.
B.
The similarity in their properties arises from the fact that they have an equal number of valence shell electrons.
C.
Fluorine, Chlorine, Bromine
Answer:
The answer is below
Explanation:
one gallon of gasoline produces 9.50 kg of carbon.
The total number of cars = 40 million
Distance covered by each car = 7930 miles
Consumption rate of the cars per miles traveled is 23.6 miles per gallon.
Hence the annual gasoline consumption by all the cars in the United States of America = (total number of cars × Distance covered by each car) ÷ Consumption rate of the cars per miles
annual gasoline consumption by all the cars = (40000000 × 7930 miles) ÷ 23.6 miles/gallon = `1.344067797 × 10¹⁰ gallons
1.344067797 × 10¹⁰ gallons = 
The symbol : 
<h3>Further explanation
</h3>
There are two components that accompany an element, the mass number and atomic number
Atoms are composed of 3 types of basic particles (subatomic particles): <em>protons, electrons, and neutrons
</em>
The Atomic Number (Z) indicates the number of protons and electrons in an atom of an element.
Atomic number = number of protons = number of electrons ⇒ neutral number
Atomic mass is the sum of protons and neutrons
Atomic Number (Z) = Atomic mass (A) - Number of Neutrons
The element has 71 electrons and a charge of +1 , so
Number of protons = 71 + 1 = 72
Number of protons = the atomic number = 72
The element with atomic number 72 is Hafnium(Hf)
The atomic mass of Hf = 178 g/mol
Answer:
true I think but I am not sure
Explanation:
I hope it's help u :)