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marysya [2.9K]
3 years ago
8

PLEASE HELP ME ASAP: Some students are using samples of different substances for a lab investigation. They plan to observe the p

hysical properties of each substance and record their observations in a table like the one below.
Which of the substances observed are elements?

Chemistry
1 answer:
marin [14]3 years ago
3 0

Answer: S,Fe,O2,Sr, and Al

Explanation: I saw it on quizlet

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Artyom0805 [142]
The answer is 5.4! I found it on a an online calculator! 
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3 years ago
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Compare which element would have larger first ionization energy: an alkali metal in Period 2 or an alkali metal in Period 4?
maria [59]

Answer:

An alkali metal present in period 2 have larger first ionization energy.

Explanation:

Ionization energy:

The amount of energy required to remove the electron from the atom is called ionization energy.

Trend along period:

As we move from left to right across the periodic table the number of valance electrons in an atom increase. The atomic size tend to decrease in same period of periodic table because the electrons are added with in the same shell. When the electron are added, at the same time protons are also added in the nucleus. The positive charge is going to increase and this charge is greater in effect than the charge of electrons. This effect lead to the greater nuclear attraction. The electrons are pull towards the nucleus and valance shell get closer to the nucleus. As a result of this greater nuclear attraction atomic radius decreases and ionization energy increases because it is very difficult to remove the electron from atom and more energy is required.

Trend along group:

As we move down the group atomic radii increased with increase of atomic number. The addition of electron in next level cause the atomic radii to increased. The hold of nucleus on valance shell become weaker because of shielding of electrons thus size of atom increased.

As the size of atom increases the ionization energy from top to bottom also  decreases because it becomes easier to remove the electron because of less nuclear attraction and as more electrons are added the outer electrons becomes more shielded and away from nucleus.  Thus alkali metal present in period 2 have larger ionization energy because of more nuclear attraction as compared to the alkali metal present in period 4.

6 0
3 years ago
Define the boiling and evaporation using kinetic theory
expeople1 [14]

Answer:

Explanation:

By the kinetic molecular theory (particle model), all matter consists of particles, there are spaces between the particles, the particles are in constant random motion, and there are forces of attraction and repulsion between the particles.

Furthermore, temperature is defined to be a measure of the average kinetic energy of the particles.

Evaporation is a change of phase from liquid to gas explained as follows :

When particles in the liquid phase are heated, they gain kinetic energy and move faster and further apart. Eventually they have enough energy to escape the forces of attraction holding them together in the liquid phase and they move very fast and far from each other and exist in the gaseous phase.

5 0
2 years ago
What is true about: Na+1?
AlexFokin [52]

Hey there!

Na is sodium, which has 11 protons.

The more realistic amount of neutrons for this atom to have is 12. 23 would be the sum of protons and electrons.

The atom has a charge of 1+, so there is one less electron than protons, so

11 - 1 = 10 electrons.

Your answer is d. it has 11 protons, 10 electrons, and 12 neutrons.

Hope this helps!

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