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2 years ago

What is the difference between a period and a group in the periodic table?

2 answers:

6 0

A period is horizontal; the elements gain 1 proton for each space moving left to right.
A group is vertical; the elements in each group have the same number of electrons in the valence shell(outer orbital).

Alexeev081 [22]2 years ago

3 0

In the periodic table, the vertical columns are called the “groups” or sometimes referred as “families.” They are called this because they have similar chemical properties. The horizontal rows on the period table are called periods because they all have same exact number of electron shells.

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Write the net ionic equation for the precipitation of cobalt(ii) carbonate from aqueous solution

andrey2020 [161]

Missing question: Write the net ionic equation for the precipitation reaction that occurs when aqueous solutions of ammonium carbonate and cobalt(II) bromide are combined.<span>Balanced chemical reaction:
(NH</span>₄)₂CO₃(aq) + CoBr₂(aq) → CoCO₃(s) + 2NH₄Br(aq).
Net ionic reaction:
2NH₄⁺(aq) + CO²⁻(aq) + Co²⁺(aq) + 2Br⁻(aq) → CoCO₃ + 2NH₄(aq)+ 2Br(aq).
or CO²⁻(aq) + Co²⁺(aq) → CoCO₃(s).

4 0

2 years ago

When a mercury-202 nucleus is bombarded with a neutron, a proton is ejected. What element is formed?

Galina-37 [17]

That will make a gold-202 nucleus.

<h3>Explanation</h3>

Refer to a periodic table. The atomic number of mercury Hg is 80.

Step One: Bombard the $\displaystyle ^{202}_{\phantom{2}80}\text{Hg}$ with a neutron $^{1}_{0}n$ . The neutron will add 1 to the mass number 202 of $^{202}_{\phantom{2}80}\text{Hg}$ . However, the atomic number will stay the same.

New mass number: 202 + 1 = 203.
Atomic number is still 80.

$^{202}_{\phantom{2}80}\text{Hg} + ^{1}_{0}n \to ^{203}_{\phantom{2}80}\text{Hg}$ .

Double check the equation:

Sum of mass number on the left-hand side = 202 + 1 = 203 = Sum of mass number on the right-hand side.
Sum of atomic number on the left-hand side = 80 = Sum of atomic number on the right-hand side.

Step Two: The $^{203}_{\phantom{2}80}\text{Hg}$ nucleus loses a proton $^{1}_{1}p$ . Both the mass number 203 and the atomic number will decrease by 1.

New mass number: 203 - 1 = 202.
New atomic number: 80 - 1 = 79.

Refer to a periodic table. What's the element with atomic number 79? Gold Au.

$^{203}_{\phantom{2}80}\text{Hg} \to ^{202}_{\phantom{2}79}\text{Au} + ^{1}_{1}p$ .

Double check the equation:

Sum of mass number on the left-hand side = 203 = 202 + 1 = Sum of mass number on the right-hand side.
Sum of atomic number on the left-hand side = 80 = 79 + 1 = Sum of atomic number on the right-hand side.

A gold-202 nucleus is formed.

6 0

2 years ago

Calculate the Cal(kcal) in 1 cup of whole milk: 12 g of carbohydrate, 9 g of fat, and 9 g of protein.

laiz [17]

Fat: 1 gram = 9 calories Protein: 1 gram = 4 calories Carbohydrates: 1 gram = 4 calories Alcohol: 1 gram = 7 calories"
So, (12 g carbohydrates)*4 Cal=48 Cal; (9 g fat) *9 Cal=81 Cal; (9 g protein)*4 Cal=36 Cal
48 Cal + 81 Cal + 36 Cal = 165 Cal in one glass of milk

5 0

3 years ago

Read 2 more answers

Thomas has 235 grams of K2S in the chemistry lab. How many atoms of potassium (K) are in 235 grams of the compound?

iVinArrow [24]

The number of atoms of K that are in 235 g of the compound is

2.57 x10^24 atoms

calculation

Step 1: find the moles of K2S

= moles = mass/molar mass

= 235 g/110 g/mol= 2.136 moles

Step 2: multiply 2.136 moles by no. of K atoms in K2S

= 2.136 x2 = 4.272 moles

Step 3: use the Avogadro's law to determine number of K atoms

that is according to Avogadro's law 1 mole = 6.02 x 10^23 atoms

4.272 moles= ? atoms

by cross multiplication

= (4.272 moles x 6.02 x10^23 atoms) / 1 mole = 2.57 x10^24 atoms

4 0

3 years ago

Choose a sport or sporting play. Describe the types of energy involved in playing the sport. State whether playing the sport is

Wittaler [7]

I’m epic $$$$$$$$$777$$777$$$$$77777777$$

8 0

2 years ago