Maria examines a mixture that appears to be the same throughout. however, when she looks at a sample using a magnifying lens, she can see small droplets of liquid surrounded by another liquid. which conclusion best fits her observations? the mixture is a solution because it has the same appearance throughout the sample. the mixture is a suspension because it is composed of two different-appearing substances. the mixture is a heterogeneous mixture because one liquid is dissolved in the other. the mixture is a colloid because two different substances can be seen in a small sample.

Answer is: The mixture is a colloid because two different substances can be seen in a small sample.

Colloid is microscopically insoluble particles that are suspended throughout another substance. For example whipped cream and gelatin.

For example, in the presence of an emulsifying agent, a mixture of oil and water becomes a colloidal dispersion.

Colloidal dispersion otherwise colloid is a system, in which discrete particles, droplets or bubbles of a dispersed phase (in this case oil), whose size at least in one dimension is in the range from 1 to 1000 nm are distributed in the other, usually continuous phase - dispersion medium (in this case water) differing from the dispersed phase in composition or state of aggregation.

first one is the correct answer

assuming that your periodic table has eighteen columns, you should highlight   the four elements in the third column from the left of the table.

neutral atoms of elements after calcium contain d electrons. the energy of d orbitals of a particular main shell lies between the energy of the s and p orbitals of the next main shell. for example, electrons in the have energy higher than those in the orbital while lower than those of the orbital.

by the aufbau principle, electrons fill orbitals one at a time, starting from those of the lowest energy. the orbital is therefore filled right after orbitals and before orbitals.  

potassium has electron configuration and calcium . the s orbital of a main shell holds a maximum of two electrons. the next element would thus have the electron configuration and satisfy the requirements.

a neutral atom of the element contains three electrons on top of the most recent noble gas element. it should thus be placed in the third column of the periodic table. both scandium and yttrium would satisfy the conditions. an aufbau diagram indicates that the 4f orbital is filled before the 5d. however, it appears that exceptions exists for both lanthanum and actinium. neutral atoms of the two d-block elements also demonstrate the and should be highlighted as well.