Answer:
D- a weak base
Explanation:
The ph scale goes from 1-10 a solution over 7ph is classified as basic. A solution thats 8.4 is only 1.4 over 7pH, making it a weak basic solution. An example of a strong base would be a solution with a pH of 9.2 (for example).
It's b. calcium
because the outer electron structure in all of that element is similar, they have the same chemical and physical properties.<span />
Answer:
They are classified as METALS.
Explanation:
Elements are simple substances that cannot be chemically broken down into smaller substances. Based on different characteristics, they are classified into 3 namely:
- metals
- non metals and
- metalloid( mainly act as semi- conductor).
METALS are the type of elements that loses electrons to form positive ion, that is, they are electropositive elements. They are distinguished by the following characteristics:
- LUSTROUS: they have the ability to reflect light from its surface.
- At room temperature: Metals are solid are room temperature with the exception of Mercury which is liquid at room temperature.
- They react and form Basic Compounds
- Great conductor: most metals are great conductors of heat and electricity because they possess free electrons.
- Melting Point: they have high melting points.
Answer is (2) - hydrogen carbonate
<em>Explanation:</em>
NaHCO₃ is an ionic compound which is made from Na⁺ and HCO₃⁻ ions. The decomposition is
NaHCO₃ → Na⁺ + HCO₃⁻
Among the resulted ions, Na⁺ is a monatomic ion while HCO₃⁻ is a polyatomic ion.
<em>Polyatomic ions mean ions which are made of two or more different atoms.</em>
HCO₃⁻ is made from 3 atoms as H, C and O. The name of HCO₃⁻ ion is bicarbonate or hydrogen carbonate.
Answer:
It can help identify elements quicker.
Explanation:
