Answer:
Explanation:
1. Atomic numbers:
Atomic number is the number of protons in an atom. It is one of the most diagonistic and representative number used in identifying an atom. The periodic table of element arranges elements based on this number.
No two elements have the same atomic number.
Protons are positively charged particles in an atom.
- In a neutral atom, the atomic number is the same as the number electrons since electrical neutrality is attained when the number of protons and electrons are the same.
- The atomic number determines the position of an atom on the periodic table and it is unique for every atom.
2.
Periodic patterns
These are trends on that can be predicted on the periodic table because they shew regularities down a group or sometimes across the period.
Some of these trends are atomic radius, electronegativity, metallicity, nuclear charge e.t.c
Properties of elements can be predicted using these patterns even before they are discovered.
b.
Physical property shared by Helium, Argon and Neon is that they are all gases. All group 8 elements are called noble or inert gases.
Chemical property of these elements: they are chemically unreactive.
These gases are very stable having complete electronic shell configuration. Every atom on the periodic table tries to attain the state of the noble gases.
C.
Noble Gases/ Inert Gases/ Group O elements
You can have a solution of hydrogen peroxide that might say 10% that means that 10% per mass of the hydrogen peroxide solution is the hydrogen peroxide the rest is water.
concentration is the amount of mass in the solution eg 5gdm-3
hope that helps
Answer:
7.98 × 10^3grams.
Explanation:
To find the mass of fluorine in the number of atoms provided, we first divide the number of atoms by Avagadros number (6.02 × 10^23atoms) to get the number of moles in the fluorine atom. That is;
number of moles (n) = number of atoms (nA) ÷ 6.02 × 10^23 atoms
n = 2.542 × 10^26 ÷ 6.02 × 10^23
n = 0.42 × 10^ (26-23)
n = 0.42 × 10^3
n = 4.2 × 10^2moles
Using mole = mass ÷ molar mass
Molar/atomic mass of fluorine (F) = 19g/mol
mass = molar mass × mole
Mass (g) = 19 × 4.2 × 10^2
Mass = 79.8 × 10^2
Mass = 7.98 × 10^3grams.
Answer:
1) Basic
2) Basic
3) Acidic
Explanation:
pH of a solution is a measure of the H3O+ ions in the solution and hence reflects its acidity.
![pH = -log[H3O+]](https://tex.z-dn.net/?f=pH%20%3D%20-log%5BH3O%2B%5D)
Solutions are classified as acidic, basic or neutral based on the pH range
-pH < 7, acidic
- pH = 7, neutral
- pH > 7, basic
1) [H3O+] = 2.5*10^-9M
![pH = -log[H3O+]=-log[2.5*10^{-9}]=8.60](https://tex.z-dn.net/?f=pH%20%3D%20-log%5BH3O%2B%5D%3D-log%5B2.5%2A10%5E%7B-9%7D%5D%3D8.60)
Since pH > 7, solution is basic
2)[OH-] = 1.6*10^-2M
![pOH = -log[OH-]=-log[1.6*10^{-2}]=1.80](https://tex.z-dn.net/?f=pOH%20%3D%20-log%5BOH-%5D%3D-log%5B1.6%2A10%5E%7B-2%7D%5D%3D1.80)
pH = 14 - pOH = 14 - 1.80 =12.2
Since pH > 7, solution is basic
3) [H3O+] = 7.9*10^-3M
![pH = -log[H3O+]=-log[7.9*10^{-3}]=2.10](https://tex.z-dn.net/?f=pH%20%3D%20-log%5BH3O%2B%5D%3D-log%5B7.9%2A10%5E%7B-3%7D%5D%3D2.10)
Since pH < 7, solution is acidic
